Seraph

Seraph have low base stats but plenty of growth, giving them a lot of potential as a solid all rounder.

Strategies
They don't have much in the way of a skill pool which gives you some freedom in customization. Don't be afraid of giving them skills that'll make them go through lots of mana either, as they have ManaDrain and the toughness to make use of it on the frontline.

Breeding
Incredibly low Fertility/Virility makes them dismal at Breeding.