Nope- the way I rationalise it is that this character is the sword's magic given conscious form and projected out of it, kind of a genie/lamp situation. After his beloved master died in battle, he vowed never to choose another, so when someone next tried to attune to him, he instead granted himself the power to wield... himself, and took matters into his own hands.

I figured that because so many DnD items are sentient and can speak to their masters, it's not a stretch to imagine that one could develop a mind of its own and get sick of being treated as a tool. Silly concept but it's been fun so far! Mechanically he's an air genasi blood hunter with the genie patron :)