Tight corridors and assassins means you need some back line tank squads, but the enemy dark mages are the biggest threat here. You’ll want a squad or two that has magic resistant characters like paladins, valkyries, characters with high magic and/or an artifact that resists dark magic. Avoid using Excalibur (weak to dark magic). There are also tons of shadowy corridors in this stage: remember that they also serve as ambush terrain.

Many of the enemy squads are Zanatus fanatics who will not surrender, no matter what. Most of these squads start with Fearless morale, but a few of the other squads refused to surrender to me even with the Skull of Rowdain.

At the start of turn 2, two more assassin squads will arrive from the right tunnel. These squads both have five assassins and two rogues, so consider an archery barrage first. Another two assassin squads will arrive at the start of turn 5, but from the left tunnel this time. If you were be expecting another assassin squad from north tunnel on turn 6, you wouldn’t be disappointed.

The trickiest part of this stage is exiting the single file corridor into the large room of mage and crossbow squads. I recommend sending in a defensive squad with exemplar on them to bait out a few of the enemy. Next turn you can have the horse archers soften them up and follow up with blessing and teleport to get extra attackers into position to wipe out/severely weaken the mages. Meteor is a nice bonus if they line up in all together.

Now for the home stretch. Pay careful attention to the movement range of the sisters of mercy (the priestess squads) and stay out of their range to avoid triggering their attack. This is straight forward for the treasure chests and crossbows who aren’t that big of a threat, but the last cluster of three dark mages is quite close to a few of the sisters. Use ranged attacks and/or hit and run with cavalry to avoid getting in range of the sisters of mercy. You can talk to Edelia with Diana if you want, but it’s not required. I tend to kill the middle and right dark mage squads first. Then I can send Diana up to the space the middle mage occupied to talk to Edelia and attack the left dark mage squad. If Diana can’t finish the last dark mage, make sure you have someone else in reserve to do so.

This is one stage where I usually don’t make the turn limit, but I’m typically almost to tech maximum at this point. So I’d rather go safe and slow than risk a death for a few more faction xp.

Interlude

Edelia will join Diana’s squad if there’s space, even if she doesn’t have capacity available. Otherwise Edelia will be in your reserves and you can add her to another squad, but it feels thematically right for her to be in Diana’s squad!

I splurged on another sunstone, another obsidian and hired a lightning sword master. She had Knight Captain, which I won’t use, but I really want a few more sword masters to experiment with some light squads. I almost never use assassins, but there was a unique asassin, Cutthroat Kloc, so I’ll give him a try in Jaromir’s Skull of Rowdain squad. Maybe his ability to hit the backline will help even out the damage more? His strength of 47 doesn’t seem particularly promising, but he likely gets some heavy bonuses for the stealth attack damage.