Anyway, let's look at the battle.
~250 zombies
~60 skeletons
~10 hollow remains
8 wights
vs
42 soldiers, 51 monks
Results in :
~115 zombies, ~25 skeletons lost
Significantly less than ~20 soldiers ~25 monks lost
So, basically, even with a 3:1 numerical advantage and a perfect ambush, we still lose more than 3 zombies for every target we kill.
The enemy still has 44 soldiers and 52 monks left. That's 300 zombies worth.
I am not actually sure that we want to burn the place down considering valuable goods and desire to use the fortress for ourselves but I am worried about possible reinforcements including something nasty like the angel coming to their aid.
The valuable goods are in warehouses outside the main building. The fire would be limited to those. As for using the fortress ourselves, we don't have the resources to hold it.
Why don't we poison the well. Oldest trick in the book, with no portable water they'll have to give in. Their reliance on a spring likely means that they'll lack cisterns and other storage methods. Further, let's burn some mental might sending visions and dreams and such to convince people we wI'll be merciful should they surrender.
Edit: also send in some sort of plague, or an imp that spreads disease.
It's seems an easy and obvious thing, but I fear for the existence of magic water purification techniques.
and our Brutewolves, led by our canine daughter will run them down when they rout.
you seriously overestimate brutewolves here. BTW, Our daughter is a child and she is weaker than... pregnant Kate
Yu, remember. Two brutewolves vs 2 soldiers => both brutewolves died.
They can't bite through armor.
Anyway, a plan, based partially on Strongpoint's plan.
~135 zombies, ~35 skeletons, 10 hollow remnants, 20 spectres, 8 wights, 6 brutewolves, 5 midnight imps, 2 black imps, 2 rock trolls, Malkus, 14 cultists, 1 Wolfmaster, Mkilzk
Prep phase :1) Loot enemy corpses to arm cult of the wolf and\or hollow remains. Pile remains of the fallen enemies mixed with zombie chunks and put the whole thing on fire. Use evil fumes generated to teach Mkilzk how to manipulate smoke. Sneak the smoke upwards towards the temple, drenching the entire Temple in the sweet mouth-watering smells of roasted human ribs.
2) Sends Spectres out to scout. We don't want to be caught unaware by reinforcements. Should any be on the way, we will cancel all plans below this point, leave the zombies behind, sneak by the rescuing army and attack some of the now unprotected villages that army was defending.
3) Traitors will argue that the fortress needs to be prepped for more defensive action. Barricade entrances, windows and all that. This will make it harder to get in,
or out.
4) A message will appear, written on the wall in unremoveable smokey letters. It would proclaim that we (the demon) have decided to reward them for their good fight, and have enchanted the spring water to heal wounds. The water will be perfectly ordinary. Use our mental powers to intensify paranoia about this undetectable demonic influence, hopefully causing many to forgo drink.
5) The wolf cult has not much to do. They can range out and look for local wolves to recruit, or something.
The burning6) Traitors, midnight imps and trolls will use various means to start fires within the central compound. Using our control of smoke, we will keep it there, within and surrounding the temple.
7) Under the cover and panic of smoke, begin moving the zombies upwards to cut down any escaping stragglers.
Use this giant sacrificial pyre to summon something neat.
On a side note, one of the primary issues with zombies is that they're literally braindead. Malkus has to micromanage them to get them to do anything at all. As such, I propose we create sort of unit for later on.
CryptbrainAn undead with minor necromantic powers, which it uses to control other undead and lead them in battle. Similarly, it can use these powers to mold and repair undead, reattaching or reanimating lymbs. Cryptbrains are actually quite smart, but tend to be weak at least initially. They are perfectly aware of their weakness, and thus tend to use their necromantic power to upgrade themselves with the best bits of their fallen subordinates.