New units in Necropolis. Discussion and selection between upgrades.

No, on the contrary, I think Necromancers capture all the mines very quickly at the beginning by raising undead...

Well, it also depends on the hero. Take Kaspar, for example; with him, you can conquer mines much faster and with fewer losses, or even without any losses at all, compared to someone like Naadir, who would lose twice as many troops!