The most powerful warrior.

These creatures are tough, but you can only capture someone on the 2nd turn, and even then, only one stack.

But they have 181 HP, so I wasn't counting on capturing them, but rather on killing them with ranged attacks.

I just learned about morale, and does increasing it also not affect them?

I don't know about increasing it. It seems to have an effect, but the necromancer's wails don't.