Harmony - Troop Symmetry

The hero supposedly moves closer to the unit and draws life energy from the enemies it has killed, and then the unit heals itself.
Vampires take this energy for themselves.

Well, I guess this is just a personal interpretation – there's nothing like that in the lore, and the description of the spell and its effect speaks of a temporary transformation of the unit.
We need to come up with a name for this spell; I think "... ritual" or "... rite" would work.