Tip: Invading heroes?

[TigerBlood]

You might want to equip your valuable commanders with cheap shields, or other missile defence, as one of the Trolls will fire at commanders.

Bodyguards will help defend against the Dark Knight. Lots of blood slaves will do in a pinch, but you would be better off using decent fighters.

You might want a mage summoning chaff units to counter the Ghost Wolves. Imps would work if you have a spare blood mage. Otherwise a large squad of infantry would be enough.

You might have some luck with a communion/sabbath followed by hellbind heart, but expect to lose a few communicants. You'll want a minimum of 2 slaves, preferably more than 4, as well as multiple masters.

Failing that, you could just attack with about 40 heavy cavalry. Just make sure you have a few spare commanders handy. You'll probably lose about half, but you stand a good chance of taking most of them out on the first attack.