This I will take the time to better explain.

The Overdrive isn't a single spell, but numerous different spells that operate on the same basic principle. Each technique and effect is its own spell, they are all just closely related in their metaphysical mechanics.

The vampire killing relies on the "associations" of the Life affinity. Vampires are undead, which is the polar opposite of Life. The spell essentially works like 1 + -1 = 0 and destroys the undead by metaphysically neutralizing them. "Revive kills zombies," in other words.