Echoes of the Void

So... I killed Ishibala and the necromancer who was bringing reinforcements. The reinforcement unit turned out to have 2 hired Rakshasa princesses, which made the fight with him 10 times harder than with Ishibala himself.... To make matters worse, right after the two necromancers, the demon Grok arrived, but he didn't join the fight. He ran around for a bit and then left. And then... three days after Ishibala's death... Ishibala comes back... He takes the garrison with losses, and then he gets reinforcements, and in the end, he has 15 liches, almost 200 skeletons, about a hundred of each grade, and the rest are undead. I have 60 militia, 40 archers, and 10 swordsmen. If it weren't for those Rakshasas, I would have had 150-160 militia. But that's not the main point. Also, on the same day as Ishibala, a dark elf arrived... There are too many heroes to defeat, so I'm lowering the difficulty level.