Sworn enemy.

By the way, there's no need to complain that the "Cursed" spell is a weak special ability. It's not hard to find enemies on the map and put them under the effect of the spell. It's enough to put 2 enemies under the effect (an Elf can put up to 5, and there's an 80% chance of finding 2 enemies in the enemy army on the map), and the enemy army is already reduced by 2/7.