Strife:Devourer

When equipped (acting as a two-handed weapon), each spell cast by the user has dM+N magnitude.

Upon acquiring Devourer, N starts at 0 and M starts at 20. M increases by 1 each entity killed by one of your spells with Devourer equipped, and N increases by 1 each spell critical success landed with Devourer equipped. These values will stay the same so long as Devourer is in your inventory; it preserves the values even if de-equipped.

You can also use it to hit people as a weapon, though much worse than any spell you cast alongside it. If you kill an entity with Slash damage it will add (entity killed character level)/4 to M and N, if you kill an entity with Chop damage it will add (entity killed character level)/2 to M and N, and kill an entity with Slash damage it will add (entity killed character level) to M and N.