Northern Rebirth

All you can recruit in this scenario are level 0 Peasants and Woodsmen, so it calls for unusual tactics. Initially you can't overpower the orcs by brute force. Fortunately though, the orcs are fighting amongst themselves, so guerrilla tactics will work. Keep your head down, and let the orcs weaken each other while you slip around the edges and grab as many villages as you can - even if you have to sacrifice a few units. Once the orcs are done fighting (one side will be mostly out of units), march your Woodsmen in a line and finish them off.

The next scenario can be expensive, so try to finish as early as you can. Don't worry too much about leveling troops (except for Tallin and Zlex), because you'll get better troops next scenario anyway. When you do level units, keep in mind that you'll mostly be fighting skeletons for the next four scenarios; Bowmen will be okay late-game but not so good in the near future.

Also, beware of the tunnel entrance to the northeast. When you move there you will unleash a squad of trolls. Sometimes they attack the orcs (good for you) but other times they attack you. Since they are resistant to your pierce attacks, they can give you a bit of trouble should the latter happen.

Infested Caves

Objectives: Find the dwarves and survive; or, defeat all the enemy leaders
Lose if: Tallin or Hamel dies or turns run out
Turns: 60/55/50/45 (easy/medium/hard/nightmare)
Starting units: Tallin and a supporter
Other: find Camerin the Arch Mage in the northernmost village

This will be a long write-up, because this is a difficult scenario that stumps many players.

First, here is the big picture. If you play just a few turns into this scenario, you will readily notice the green and blue Troll Whelps, the orange and white Skeletons, and you'll probably soon see the brown level 2 trolls coming from the far side of the large chamber. All of these have a cache of villages behind some sort of chokepoint, which means that they won't run out of money and fresh recruits. Once you make it past the brown trolls, you'll come across another castle of skeletons, then finally, the home of the dwarves. Trolls, skeletons, and dwarves will all fight the others, given the chance. Depending on much randomness and the difficulty level, the dwarves may kill their adjacent undead leader and show up in the main hall as early as turn 15, or they may be stalemated by the skeletons until the end of time.

Now, let's have a look at the troops at your disposal:

Footpads' don't have many HP, but also tend to take little damage due to their dodge rating. They're also quite fast. However, their damage output is (barely) sufficient against skeletons and totally inadequate against trolls -- they won't get pushed back, but won't push forward either. Still, footpads should make up the bulk of your army: As you lack healers, your troops need to run back back to a village when they get beat up. Footpads run faster and take less damage than your other units.
Thugs, with their powerful impact attack, will do more damage than anyone else. However, being melee-only means they get beat up in the process, not to mention shot to pieces by the Skeleton Archers. Pulling them back for healing takes a lot of time. Having a thug in the right place at the right time can make quite a difference... but you don't need them to finish this level and probably won't ever recall them later.
Poachers are virtually useless against skeletons, but the best ranged attackers against trolls. Later (much later) you will need a few good archers, and now is the time to train them. Something like four or six will probably be enough, though.

Next, let's examine your opponents. The area in the east around the brown trolls is the key to winning this scenario. But let's start with the minor opponents, the four teams of level-1 trolls and skeletons closest to your initial keep. Sealing them at their chokepoints is easy. Generally, you should immediately send off some footpads towards each of the four, occupy a favorable line of defense, then reinforce them over the next couple of turns. If and when you defeat any of the four, you'll discover a secret passage to their neighbour. Meanwhile, additional troops should assemble in the main hall for the fight against the brown trolls. All told, you will need like 40 men and could use many more -- if you don't have at least 500 gold to begin with, revert and replay the previous level, shooting for more like 800 gold.

There are six opponents in all:

1) The blue trolls (north). There's village on a small patch of meadows where you'll discover a level-3 mage who will join you. Get there quickly or you won't make it until much much later. If you want to stalemate the blue trolls, put a Footpad on the mushroom patch and another unit on the cave hex. There are other possible stalemate lines if you need to fall back. You can kill this leader by an assault up this tunnel, but it will take some time unless you get lucky.

2) The green trolls (south). There are two excellent stalemate lines here. In the 2-hex wide area, the village close to your keep and one adjacent hex behind are great for quick Footpads, which can dart off to another village to heal if necessary. The other stalemate line is in the 3-hex wide area, where there is a village and a mushroom patch opposite. Putting a third unit in the middle and behind for a U-shaped line allows you to get three attacks on one, whereas the enemy can only muster two attacks on one. If you want to kill the green troll leader instead of just stalemating him, you'll need to be more aggressive, moving as far forward as quickly as possible. With your troops closing in on his keep, the leader will occasionally take part in the fight -- eventually this will be his downfall.

3) The orange skeletons (east then south) can be totally contained with a couple of Footpads initially. The trolls will come to help. On harder difficulty levels, you may want to widen the containment area so that a few orange skeletons enter the main chamber; this will attract more trolls to bash on the skeletons, which means less trolls bashing on your troops.

4) The white skeletons' exit (east then north) is extremely easy to guard -- just see to it that you get there in time. But hey: there's a second hole further down the hall, pretty close to the brown trolls. For now, that's in your favor. After the brown trolls have been defeated, you can loosen your grip on the first gap -- his skeletons will prefer that outlet and leave the second corridor unguarded. You can then march a whole army up there and occupy about ten white villages. Deprived of his income, destroying the white leader will be standard procedure.

5) The brown trolls (east). Occupy the castle ruins and rugged terrain in the center of the large cave, but not before most of the trolls have moved off to fight the orange and white skeletons. You may try to lure out the troll leader and pin him down, or just rush in and occupy his castle. Just make sure that he can't recruit anymore. Killing him may take several turns and will certainly cost you some units, but as long as you keep him from recruiting, things will work out. Also remember that there's another set of skeletons behind the trolls. On the harder difficulty levels, the undead will be ready to burst out of the southeast tunnel by turn 13; you will want to arrive before, so that you can contain them.

6) The final skeletons (southeast) you'll find past the trolls are in a battle with the dwarves. On the easier difficulty levels, it's is even possible they no longer exist, as they may have succumbed to the dwarves. On the harder difficulty levels, these skeletons have probably stalemated the dwarves and have turned their attention to an assault on the trolls and you. Once these undead are gone, the dwarves will pour out and "help" you with the remaining opponents, stealing kills and standing in the way. You should maybe fill up the corridor just south of the brown trolls' fortress with units of your own, just to keep the dwarves away. Peasants will do. Also don't forget to seize the dwarven villages - there's quite a few.

Finally, here are strategies players have used with success...

"Total victory" strategy -- Technically speaking, it would suffice to win if you somehow manage to move Tallin into the dwarves' home without killing any enemy leaders. However, this requires that you somehow get past the brown trolls; if you can do that, you can just as well rub them out. On the easier difficulty levels, killing all the other enemy leaders on top of the brown troll leader isn't difficult but takes some patience. On easy, you've got 60 turns, and even if you need 40 in order to clear the map, you're still in for a huge early finish bonus, which you'll really need later on. Advance with all haste on the blue trolls, green trolls, brown trolls, and/or white skeletons (using the eastern entrance or the secret passage from the blue trolls); use their villages to build a massive army for the rest.
"Migration" strategy (as per HomerJ's forum post) -- On the harder difficulty levels, a total victory might not be possible and even just getting Tallin to the dwarves will require a carefully choreographed ballet, playing off the trolls against the skeletons. First things first: rescue the Arch Mage and send him to join your main army. Using Footpads, set up containment lines against the blue trolls, green trolls, white skeletons, and orange skeletons. In the main chamber, the trolls there will be more interested in fighting the skeletons than your troops, if you keep them healthy and on good terrain. Around turn 8, after most of the brown trolls have joined your Footpads against the skeletons, move the bulk of your army into the main chamber. Fan your Footpads out, grabbing fortress hexes and other good terrain, creating a pocket for your more vulnerable units inside. By turn 12, you need to be in the brown trolls' keep so that you can block the undead that are about to burst out of the southeast passage. Meanwhile, you should "release the hounds" - remove the stalemate lines against Troll Whelps in the west, allowing them to pour into the main chamber. This will entertain the orange and white skeletons for quite some time, preventing the skeletons from endangering your new home in the east. The brown trolls have a cache of villages just northeast of their keep, so grab those, start generating income again, and recruit units as needed. Set up a defensive line along the western edge of your new keep, while advancing through the southeast tunnel and killing the undead leader there. Raid the dwarven villages for income and wait until the last turn to move Tallin to a dwarven castle hex.

To The Mines

Objectives: Go to the mines (with Tallin) or defeat the wolves
Lose if: Tallin or Hamel dies or turns run out
Turns: 40/36/30/24 (easy/medium/hard/nightmare)
Starting units: Tallin, Hamel, Camerin and a supporter

This is designed to be more of a breather scenario, letting you get a bit of fresh air and level a few units before you plunge back into the caves. However, stay on your guard because if you get sloppy, you could experience a lot of grief.

The basic strategy is to recruit lots of dwarves and sweep north in a line. You'll lose a few but level up more, which will be your most reliable heavy infantry in later scenarios. Beware Wolf Riders nipping around your flanks and don't leave any units isolated. Recalling Poachers/Trappers will make quicker work of the Wolf Riders but the experience may be appreciated more if it is doled out to dwarves.

Alternatively, recruit a keep full of level 0 "targets" and make a point of leaving one or two of them isolated (but with support troops nearby). The AI loves to attack these "soft" targets, leaving his units vulnerable to your full counterattack. With a bit of luck, you can even lure out the enemy leader for an easy (and early) finish.

Clearing The Mines

Objectives: Clear the mines
Lose if: Tallin or Hamel dies or turns run out
Turns: 85/75/65/55 (easy/medium/hard/nightmare)
Starting units: Tallin, Hamel, Camerin, a supporter and some dwarves
Other: LOTS of ghouls show up on turn 20

This is a large scenario, and a tough one, but it's very important to do well here. There are two key secrets which will dictate your strategy.

The first secret: this is the last scenario on which you can recruit dwarfs. Dwarfs are probably the best units in your army, *especially* against skeletons; you want to recruit lots of them now, so that you can recall them later and level them into Dwarven Lords. Recruit, recruit, recruit, until you run out of gold. You should have a continuous stream of of dwarfs going both north and east.

I didn't recruit any of the Dwarvish Thunderers -- they're not much good against skeletons, and I don't like the element of randomness where half the time they deal no damage. You might feel differently.

When fighting the guard skeletons, try to lure them off their platforms before attacking. They'll cheerfully leave their posts to attack your low-level units, especially if they think there's a chance to kill something.

The second secret: see all that water on the level? On turn 21, most of that water turns into swamp, and every swamp hex will have a Ghoul on it. You need to have most of the Death Knights dead before this happens, so don't dawdle.

There are two ways to deal with the Ghouls. The first option is to kill the Lich before turn 22. This is tricky, but very doable. The Lich is very frisky about leaving his keep to attack you; lure him away and hit him with whatever Dwarven Lords you have.

The second option is to farm the Ghouls for experience. You've got lots and lots of dwarves, right? Why not have fun with them? Surround the water with dwarfs on all sides, and wait for turn 21. You'll lose a few dwarfs, but you'll gain a lot of experience, too. Be careful of the Lich, who will attack when you get close. You don't want to kill him until most of the Ghouls are dead, so it's best to just put up with him (and try not to move any high-level units where he can get at them).

The Pursuit

Objectives: Destroy Malifor
Lose if: Tallin dies or turns run out
Turns: n/a
Starting units: Tallin, Camerin, a supporter and some dwarves
Other
- Get the Rod of Justice in the northern chamber
- Raid the treasury

This level opens with an 8-way junction of passages (one of which is where you enter). Don't get involved in fights in all 7 passages at once; you can only use Camerin in one place at a time, and initially you have a serious problem with healing (namely, you don't have any means to heal units, so they just have to go and stand in the entrance passage and regain 2hp per turn).

By turn 2 you should have Tallin on the camp, recruiting thugs and recalling dwarfs. Send your best units down the southwest passage ASAP. There's a death knight down there who can recruit second-level skeletons; you have to hit him fast and hard. He won't start recruiting until you stand where he can see you, so pack the passage with units before you charge into the room. This will probably take several tries to get right.

Once the death knight goes down, your dwarf lords can clean out the next few revenants, after which the world is a much nicer place. The druid you get is pretty awesome, but the real prize here is the two invincible white mages. Whenever one white mage gets killed, the other one resurrects it, with apparently no penalty! (Resurrection seems to drain their experience, but if a white mage reaches level 3, it will stay level 3 forever.)

Your first order of business is to send the female white mage (with the "quick" attribute) down the southeast tunnel, the one with the "water monsters" warning. Send her an escort -- three or four units, any type as long as they all have 6+ movement. She'll eventually win the scenario for you.

While you've been doing all this, the death knights down the east and west tunnels have been sending skeletons at you. The bad news is it's extremely difficult to kill these guys, because the path is full of bottlenecks, and they can make a new skeleton every turn. The good news is there's not really any need to kill these guys -- put some dwarfs or thugs in the bottleneck and kill the skeletons as they come out. Fairly quickly you'll need to heal your defenders, which is why it was so important to get those healers rescued quick.

Now that you've got your base under control, it's time to focus on profit. Remember that long tunnel behind Krash? Send a footpad down that tunnel; he'll eventually find three loyal dwarfs. (He'll also find a backdoor into the Treasury, but it's probably not worth your time to send an army down that way to take advantage of it.) In the meantime, grab some healthy units and hit the Treasury from the front. When you get close, you'll trigger two Death Knights to summon units at you. Retreat out of the tunnel and kill them as they chase you into your main room, then head back in once they run out of gold.

You don't ever want to attack the guards on their platforms; instead, put an expendable unit (newly recruited Thug or Footpad) where they can reach it, and they'll leave their platform every time. Repeat until done. Your goal in the Treasury is the chest in the far north, which has 10K gold. Try not to spend too much of it. The rest of the chests have less gold, but still worth getting.

Finish the Treasury? Both the north and northeast tunnels eventually lead to the final boss, but more importantly, there's other benefits to going up the two tunnels: loads of XP and the almighty Rod of Justice.

The north tunnel leads to the Rod of Justice. The tunnel is almost entirely unguarded at first, and after a while opens into a large, open chamber. Take Tallin and the druid with a hardened force with you, because going into the chamber has two effects: your retreat is cut off by a cave-in, and you're attacked by a mass of very dangerous level 3 spiders. This is where the druid comes in: spiders have poison, and the druid can cure. Luckily, there's a chokepoint that you can fall back to and wear down the spiders' numbers before having to assault the chamber in force. The reward for killing the spiders? The Rod of Justice. When you've secured the chamber, send Tallin to go grab it. It gives him stat boosts and an incredibly powerful ranged attack.

The northeast tunnel doesn't have any big rewards like the Rod of Justice, but there are two Death Knights and loads of skeletons, making it good for experience. It's also nice and narrow, so while the going is slow, you don't have to worry about being overwhelmed.

As you've been doing all this, your white mage has been running down that long southeast tunnel. At one point her escort killed some tentacles. (And she sent a footpad down a south tunnel, where he found a friendly Wraith. Handy!) Later she passed a pool which contained a sea monster. (If you don't go in the room, it won't attack.) Eventually she reached a keep guarded by three nagas. When you're ready to take out the boss, grab your other white mage (the male one, with movement 5) and send him off to get killed somewhere. He'll teleport next to the female mage. It no longer matters if your white mages die, because they'll just respawn in the same place. Kill the nagas and open the secret door; the lich has a bunch of guards, but your white mages are invincible, and eventually (probably around turn 55-60) they'll finish the scenario for you.

[Andrew] The East tunnel has 3 holy water bottles through a hidden passage on the south side of the room.

Old Friend

Objectives: Defeat Rakshas (almost impossible) or just survive 18 turns
Lose if: Tallin dies or turns run out
Turns: 18/18/18/18 (easy/medium/hard/nightmare)
Starting units: Tallin, Camerin, Abhai, Krash, Father Morvin, Sister Thera, Elenia and a supporter

This is meant to be an easy mission if your objective is to simply survive and hoard gold. You don't have to defeat the Orcs to win this one, so you can just lurk just inside the two-hex-wide aperture of the cave only two orcs at a time will be able to get at you; it's not hard to fend them off until time runs out. Spend as little gold as possible and level up some troops.

If you are using this approach, it's worth recalling one dwarvish steelclad and run him round to the east-most village in the northern mountains - this one has impassable mountains on 2 adjacent tiles, so it can be attacked from only one tile, so a steelclad can easily hold out here & gain some XP doing so.

Alternatively, you can go ahead and sally. It is supposed to be impossible to actually defeat them entirely, but if you stick to defensive terrain and keep recycling fresh units to the front, you should soon pile up stacks of orcish corpses as well as experience, which always comes in handy. It's possible to beat the nearer two orcs with relative ease on the easiest difficulty. But not advisable. When you get too close to either of them, Rakshas triggers the appearance of Goblin Knights on all the mountain tiles in the centre of the map. This level is not possible to win by beating the leaders in the time available. But it's well worth sallying forth anyway, because you get a chance to level a lot of troops relatively easily.

[Adeptus] Block the corridor with 2 units at 1XP to increase level. The I.A. won't attack unless it has nonzero probability to kill the unit with one single attack. Skip turn 18 times (and cry for all that XP you did not gain).

Settling Disputes

Objectives: Capture the liches and save Stalrag
Lose if: Tallin or Stalrag dies or turns run out
Turns: 30/25/20/15 (easy/medium/hard/nightmare)
Starting units: Tallin, Camerin, Abhai, Krash, Father Morvin, Sister Thera, Elenia and a supporter

Your two White Mages and Camerin will be teleported into the middle of a battle between some ogres, trolls and a Lich and some dwarves. Your first job is to kill the Lich and not let the dwarf leader die. This is straightforward but Stalrag, the dwarvish leader, is quite cavalier with his life. You need to kill the Lich and then help the Ulfserkers to the south with the ogre and troll. Otherwise Stalrag will run to the village and likely be killed by the troll.

You have 100 gold, so recruit 5 good units. Your Poachers/Trappers can be used since you'll be fighting trolls and ogres with a few mages and gryphons thrown in. Assault in two places: down the east side of the map with your three mages (and any leftover dwarves) and across the river ford in the middle. Your White Mages are still immortal so you can be quite aggressive. For the river ford, you'll get across at night so be defensive (the level 2 Ogres are hard hitters) until day. (Of course, using the Rod of Justice on melee-only opponents is something that you should do all the time...) The initial wave will probably be blunted by then, too. Then sweep down and subdue the Lich.

Elvish Princess

Objectives: Survive until the end of turns or rescue the princess
Lose if: Tallin, Ro'Arthian or Ro'Sothian dies
Turns: 24/21/18/15 (easy/medium/hard/nightmare)
Starting units: Tallin, Camerin, Abhai, Krash, Father Morvin, Sister Thera, Elenia, Stalrag and a supporter

In this one it's best to go straight at Bitterhold with a small group of hardened veterans -- you need to be in there fast (Camerin and the Rod of Justice will be particularly helpful here). Your objective, getting a unit onto the cage at the center of the castle, may be best accomplished with a flyer (a Gryphon recruited specifically for this purpose can be useful) once you've chewed a few holes in the inner ring of defenders.

The Spectre, Krash and one other fast unit can usually pin down the Blue Orc leader to the East and kill him early. This is useful as it prevents him harrying your flank, and with a little support from your main force, gives you a second attack point, which helps clear the defenders quickly.

Introductions

Objectives: Move Tallin to the northern signpost
Lose if: Tallin, Ro'Arthian or Ro'Sothian dies or turns run out
Turns: 24/21/18/15 (easy/medium/hard/nightmare)
Starting units: Tallin, Camerin, Abhai, Krash, Father Morvin, Sister Thera, Elenia, Stalrag, Eryssa and a supporter

This is a small level with not that many enemies. Nothing complicated. Standard dungeon-crawling tactics should work fine in this one -- minimize your exposed front, and cycle wounded units back to the healers before they get killed. The destination signpost is in the northwest corner. Try and level any non-max-level units you still have. Send your wraith up the right-hand passage and he can attack/distract some of the trolls. There is nothing interesting in any of the side passages.

Stolen Gold

Objectives: Defeat the enemy leaders or hold out until time runs out
Lose if: Tallin, Ro'Arthian or Ro'Sothian dies
Turns: 36/36/36/36 (easy/medium/hard/nightmare)
Starting units: Tallin, Camerin, Abhai, Krash, Father Morvin, Sister Thera, Elenia, Stalrag, Eryssa and a supporter

You'll have two problems in this scenario. One is lots and lots and lots of trolls. The other is that Krash is going to fly off and recruit level-one drakes to help you, but if they get swarmed by all the level-two trolls they're not going to live long. Krash's camp will materialize in the mountains near the map-edge west of your camp; the house at edge of board will be one hex NW of his tent square. Don't do anything in the beginning with Krash except grab villages. He leaves after turn 1.

The first thing to do is kill the northwest troll. Move the Sorceress, the Ancient Lich and the Spectre towards the Blue troll on your first turn. Recall a castle of level 3s or high XP level 2s, mostly Dwarf Lords and Dragonguards, though the occasional Fugitive or Hunstman can be useful. Then move Tallin (who should be Level 4 by this stage) towards the blue leader as well. The Blue leader will take the village to the SE of his camp on turn 1. With Tallin's high movement and the power of the Lich, it's possible to ZoC him on turn 2 and kill him (it helps to use the Sorceress, she needs the XP). Then, mopping up the blue trolls is not much of a problem with the units available - apart from the sorceress, they can usually kill between one and 2 trolls per turn. Recruit a couple more troops on the Blue base if you've still got the money and attend to the rest.

I like to send the two White Mages on their own to the south. Since they are immortal they can stall the two southern trolls for (hopefully) enough time for you to kill the northeast troll. The drawback is that you go from 3 healers to just 1. If you do this, make sure to keep them in the middle of the map. Sometimes they regenerate off to the side. If this happens the trolls will just bypass them and attack your main force before you are ready.

Using your first turn recalls, establish a defensive line on the line of hills in the middle of the map at the top, putting the Shyde in the forest. Wait out the Green trolls' charge, then counterattack, bringing the Spectre and possibly the Sorceress round to help. The green troll should be on the way out around the time Krash arrives. One of the White Mages provides healing up here (if you aren't sending them on a kamikaze mission to the south).

The Lich and 2 or 3 other dwarves (healthy/resilient if possible) should hold the edge of the hills on the west side of the map, keeping them clear for Krash's arrival. They shouldn't kill any Whelps that oppose them, but take out Rocklobbers and Grunts for as little return damage as possible. Use ranged attacks in preference to melee, apart from if the Lich needs some health back. Tallin should take and hold the village in the middle when he's finished with the Blue trolls, and provide leadership. The second White Mage stays near the base, and will resurrect there when killed, providing a wonderful distraction to up to 8 trolls per turn. Krash's arrival should happen around the time that the troops from the Green troll attack are freed up - sweep all of the remaining trolls southwards. Krash and company should kill the Black leader, and the Elves and Spectre will take care of Purple around the time the Brown Elf team arrives. Good for a huge gold bonus, but requires a very aggressive start and risks losing a couple of high level units.

Alternate strategy: Recall nine or ten veterans and linger up around where his camp will appear. Hold off the troll swarm until the drakes show up, then bust out of the encirclement and clean up.

The Spectre can be extremely effective against the trolls; place him in the village on the northern tip of the eastern island, and he should be able to safely defend against one to three trolls each turn. The Elvish Shyde and Sorceress, as well as the two liches, can be put to better use if you move them into the forest on the eastern island in the beginning of the scenario. Stay within the forest and lure in trolls one or two at a time to level up the Sorceress and create a distraction. Once the troll leaders in the NE and SE have finished recruiting and their forces have moved over to attack in the west, the liches and the shyde can jump in and kill the leaders, and seize as many villages as possible.

After Krash's camp is set up, you will be controlling both Tallin's and Krash's troops. Krash's team will take its turn after all the trolls, and before Tallin. The trolls will probably be still swarming in front of Tallin's defense, but you can create opportunities for the drakes to level up by withdrawing one of Tallin's units and defeating the two trolls next to that opening, so that the trolls will be zone-locked and unable to get into the opening. The drakes will have the advantage that after they attack they can be healed by Tallin's healers, before the trolls retaliate.

Although you will be in deep negative gold during this one, don't succumb to the temptation to give all the villages to Krash. He can make use of them immediately, but that isn't important, as he starts with enough gold to recruit enough drakes for what you need. You will get a big early finish bonus, so seize villages with your forces in the east, and with your main force once you break out. It's essential to get more than 140 gold going into the next level. (Krash won't go negative, so he'll end up with 400-500 gold with the early finish bonus anyway.)

Eastern Flank

Objectives: Defeat the enemy leaders
Lose if: Tallin, Ro'Arthian or Ro'Sothian dies or turns run out
Turns: 56/53/50/47 (easy/medium/hard/nightmare)
Starting units: Tallin, Camerin, Abhai, Krash, Father Morvin, Sister Thera, Elenia, Stalrag, Eryssa and a supporter

Strategy 1: The only good thing about drakes in mountains is that you can rush them away to heal once they get trashed. They have a much lower defense on mountains relative to non-drake units. So it's better for Tallin to recall L2 and L3 dwarves (maybe one L1 dwarf), and spread these along the line in the mountains - you probably can't get enough to avoid having quite a number of drakes here, but it limits the number of drakes that the enemy can trash per turn; and the limited mobility in the mountains means they can't always attack the drakes with the units that they want.

Use drakes first to finish off weakened enemies, and drake burners to soften up the higher level enemy melee units (try to avoid having many L1 drake units in the line at night, when they are extremely vulnerable). Tallin's higher level units are better used for attacks on fresh enemy units. Don't extend your drake line to the map edge any faster than needed - the AI won't deliberately try to outflank, he'll just try to wrap around the last unit in line. You want to minimise the number of drakes he can maul each turn. Get the two human healers up into the mountains, and wounded drakes should congregate behind the lines around these. The two liches are good front-line units here, as the high defense means the enemy melee troops can't batter them too much (their drain attacks tend to compensate for any health loss), and their magic attacks are perhaps the most potent on this terrain.

Meanwhile, the east side of your line starts in the village just E of the mountains, where Tallin should be - the enemy are generally afraid to attack him due to the Rod. The line east of here consists of the spectre, the shyde & sorceress, and a mix of drakes and any high-level human units in your auto-recall. (The drakes have only a 10% difference in defense on these terrains, and have better mobility over the river.) Use the shyde and sorceress to entangle the best enemy melee units each turn, and drakes to soften up and kill them.

You hold this line for 2 days, wearing through the enemy. Once they run low on units, the drakes become valuable for encircling isolated units, rolling up the flanks, and darting behind their lines to seize villages. Push south through the mountains, and use the wizards to blast the orc leaders.

Strategy 2: I use the same technique as Strategy 1 in the mountains, but a radically different strategy otherwise. I recalled all my veterans, sent the dwarves north, and almost everyone else directly west. I recruited as many Gryphons as I could with my money, and sent them, as well as Abhai, south to take the island. I also made sure to move Tallin and Krash near to the front lines. The sheer number of high-level units attacking the main front was too much for the orcs, and by turn 11 the dwarf/drake force had defeated the northern flank. I moved Krash into one of the leader castle squares in the fortress, and recruited a Drake Burner in every free square in the fortress. (If you still somehow have positive gold with Tallin, you can use a similar technique with him) By turn 12, the orcs' main front had also collapsed due to the Drake Burners, and I defeated the last orc leader on turn 16.

The gryphons in the south basically were slaughtered by turn 10. I only had two remaining with low health; I retreated these in case they would be useful for recall (20 gold vs. recruiting 40 gold). By then, however, the island was free from orcs and there was only a small band (~5-6) of one Orcish Warrior and several Wolf Riders left. Abhai easily slaughtered most of them in the water, and the healed surviving Gryphons killed the rest by turn 14.

The only problem with this strategy is that it puts you in deep negative gold, but the early finish bonus more than makes up for that.

Strategy 3: I managed to win this scenario (on Easy) only by sending the White mages / Mages of Light to the mountains to the west of Krash, along with every dwarf lord I could recall, while the elves, Abhai, and Camerin went south of the river. I put the liches on the mountain-peninsula so that they could attack many units. Krash recruited Burners and Clashers, with the occasional Fighter, and they planted themselves in the forest and grassland west of Tallin's keep. They died easily but did not fail completely, they held the line west and I did manage to level several drakes (of each line) up to at least Level 2. This is the only way I could win without getting veterans slaughtered, and even when they weren't slaughtered, the orcs were bold enough to walk up to Tallin's keep, attack him, and steal the villages. My "advisor" was a Huntsman, who died easily, so I just kept him back. The drakes that needed healing in the field or forest took advantages of nearby villages (there were some on an island south of Tallin's keep, some in the mountains, and some in the forest). The dwarves in the mountains went into nearby villages or the White Mages if they needed healing. Abhai as a Spectre did well in the far south against Wolf Riders, and the elves and the Great Mage did well in the forest on the edge of the island against the occasional Assassin or Wolf Rider. Later, I sent a drake or two that way. Once the front line of the orcs was eliminated, Krash and Tallin moved forward with all the troops, and sat in the keeps. Because of the unique way that the castle is designed, the orcs recruited units right next to my units, while I recruited units right next to theirs. I lost a good drake or two but otherwise did not suffer many problems.

Get the Gold

Objectives: Defeat the orcs
Lose if: Tallin, Ro'Arthian or Ro'Sothian dies or turns run out
Turns: 40/35/30/25 (easy/medium/hard/nightmare)
Starting units: Tallin, Camerin, Abhai, Krash, Father Morvin, Sister Thera, Elenia, Stalrag, Eryssa and a supporter
Other: Save Sisal if at all possible. If you do, you get your gold from "The Pursuit" back

The primary challenge in this scenario is trying to save Sisal, and though it is not stated that Sisal's survival is essential, you do not get back the gold that you earned in "The Pursuit" if she dies. You really, really want that gold. Unfortunately, the AI controlling Sisal behaves strangely and she jumps into the river to be slaughtered easily. If you are desparate, an option is using the droid command to change Sisal to a human controller - that way, you control her and prevent her from dying within 3 turns.

The enemy is pretty strong so recruit with the drakes, elves and Tallin's crew. Level what units you can and focus on killing enemy units. Other than keeping Sisal alive this is a simple assault against strong enemies.

Alternative Strategy: On turn one, mass produce gliders with the drakes and gryphons with the humans. Send the gryphons along the eastern edge of the map, and send the gliders immediately due south. The gryphons will need to punch a small hole to proceed (when forces try and stop them in the mountains), but they're then easily able to wrap around to the southeast of the enemy's forces. Send the gliders to the southwest of the enemy's forces on turn three.

Throw in a few scouts from the elvish army for good measure, and you can effectively, quickly create a wall of units to shield Sisal -- at which point she returns to her keep.

This strategy also causes the AI to heavily attack your southern units, giving you a weak enemy line in the north you can quickly punch through with your massive army. I was able to defeat their leader on turn six without a problem.

Showdown

Objectives: Defeat the orcs
Lose if: Tallin, Ro'Arthian, Ro'Sothian or Hamel dies or turns run out
Turns: n/a
Starting units: Tallin, Camerin, Abhai, Krash, Father Morvin, Sister Thera, Elenia, Stalrag, Eryssa and a supporter

Pull out all the stops, because this is it. The wall is defended by level 3 orcs (Warlords and Slurbows). You'll want to draw them off the walls before engaging them, they're dangerous enough as it is without the fortification bonus; hanging a unit or two just within their engagement range will do it. Because there are so many orcs, you need to be especially careful about neither leaving units isolated nor presenting unanchored flanks for them to swarm around (the drakes, in particular, should fort up in the northern camp until they've thinned out their attackers considerably). Get to the edge of the moat and then cycle in fresh units and expand along the edge of the moat. The enemy will probably swarm towards Tallin's units. Don't try and breakthrough. Just be content to kill the units that enter the moat.

Recruit lots of druids with the elves and send them to help out Tallin and the drakes. Other than that the same strategy applies: kill the units in the moat. If there is an opening, move in.

Same thing with the drakes. If you level a Burner, turn it into a Flare. Since you have lots of level 1's the leadership will be useful.

Hamel will tear up the western edge of the fort pretty well. Aid him with elves if you can and then follow his lead to attack from within the castle walls.

Recruit, recruit, recruit, especially with the drakes. Take out the level 3 wall defenders, wear down the attackers in the moat and punch through where you can. Somewhat tedious but inevitable with your massive gold reserves.