there is already a spell which give hp, drain life, so it's pointless to create a similar spell. My idea is to have a permanent vortex which absorb the energy of the fallen creatures. The launch cost is high enough to justify a passive health recover without having it at the first turns ( a lucky hand is out of consideration ). For example, consider a match where all your creatures become plagued, at least you are repayed for the great loss of damage output and survive enough to try a revenge, imho.