Hehe, or they are favorite because they prefer to fight them instead of blackdragons or trolls :)

Well, now that I know... I will most likely only use my Rune Mage for summoning and resurrection until I find some worthy enemies. Like the undead in the first castle, who has ancient vampires - those'll make nice favorite enemies.

My Rune Mages got "skeleton archers" as favorite enemy. Wouldn't be bad (skelly archers are plentiful in game), but their damage is kind of low no matter bonuses. As with most high levels - they're good if they can attack many units with one blow, but hitting a single one - peasants would be better. Heck, level 4 demonologists and evil beholders are stronger attackers.

Specials of runemages are nice though. Curse or sheep is fun, and summons on reload too.