I agree to the 30 secs. cooldown of the Succubus' life drain ability, 60 secs. is like 1 hour for me xD, but not for the gaining of 2 extra hearts. Actually, Succubus is quite OP, you always have a 75% chance of winning in a 2v1 battle if used correctly, adding 2 extra hearts per 5 kills is way too OP. Imma suggest buffing it soon...