[Pocus]

One of my preferred leader is the Marignon initiate (65 gold) in a magic scale Marignon.

I like also to use them in battle, for 2 spells:

bond of fire, to pin down big creatures
will o wisp (one gem) which are very interesting units because of etheralness and high defence. Sure if they are hit, they die, but until then they can waste quite a number of attacks from enemy infantries.

But perhaps the Pythium Theurg is even more impressive : holy, cheap etheralizer, can cast starfires and communion.