Ragnarok

about:

Chrona's eccentric partner, Ragnarok resides within his partner's body. In addition to taking the form of a sword in battle, he can harden his user's blood for both offensive and defensive purposes. Outside of combat, Ragnarok constantly bullies Chrona in order to get his way, but follows Chrona's orders when push comes to shove. Since he is always hungry, a well-timed tread can silence his steady stream of unwanted commentary.