tactics
spell choice
These spells are worth considering:
totem of resurrection
summon demon
summon minotaur
heal
build up a force
Head right into the first hut, and plant a
totem of resurrection
at the back of the hut, and a demon
and minotaur on it.
Then head further right, and watch the mana rise.
The necromagus may turn up, but your creatures should be able to handle themselves,
and most kills will be resurrected for your team!
don't enter the castle
I personally didn't even need to get into the castle before the necromagus had fled,
and the chancellor was dead.
Perhaps I was lucky?