Ragnarök

Ragnarok is a demon sword and the weapon partner of Crona, his existence permanently altered by an experiment of Medusa Gorgon's: the witch melted him down in a vat of her Black Blood and poured the result directly into Crona's bloodstream, physically fusing weapon and meister together.

His personality matches his origins — crude, loud, and pugnacious, constantly mocking Crona's timid nature, dishing out noogies, and depriving them of sleep purely for his own entertainment. Ragnarok makes no effort to hide his cruelty, dealing out insults and nicknames to Crona as freely as to any enemy.

Despite the abuse, Ragnarok is often the one who forces Crona into action at critical moments — even if his methods are never gentle.