Eternal Lords is a fantastic addition to Age of Wonders 3.
It adds in the Undead which have been a personal favourite since AoW 2; although with a unique twist. Gone is the actual race, and instead any race and wizard can be necromancer. As such any race can be undead.
I do like the new mechanics. Especially being able to simply turn a city's population into undead, instead of suffering a penalty for migrating them out.