my overall view on the class

Looks a bit too much like a mutant mix of osa/eni/vampire to me, no offense, maybe its the horns and the wing design... But nice looks overall, just not oh so very original, at least in the Wakfu/Dofus context. :S
Background Story: Not much here, it says they were jealous of enis, then one day they changed... Yea, thats about it, Maybe more historical reference related to dofus, a reason for them not being present in the dofus story, their god, how he came to join the Amakanian panteon, etc. It also doesn't give us a clue of why they are/were jealous of enis.
You can do better on this one, c'mom.
Spells: They're ok, the "counter idea" seems interesting, but nothing is really standing out here. They look like a mix of eni's drain spell/srams poisons.
Class Overall: Its playable and totally possible, but not very special.http://forum.wakfu.com/topic.php?lang=en&id=2029&p=2