i reckon this should be called "Refuel", it would make more sense though Im not sure if that causes a discrepancy between fantasy and modern terms, though not a bad idea but i reckon it should be more like Immolation, using sacrificial methods for healing.
Just an example:
spell: Sacrifice one of your creatures. Heal yourself for X hp. X = creature's hp.
upped spell: Sacrifice all your creatures. Heal yourself for X hp. X = total hp of creatures.
since fire has more of a brutish and ambitious nature.