Nikkou

One of the only two swords in The Continent that can harm demons and Demon King. She is one of The Legendary Five that challenged Demon King Gele 1500 year ago. She was a samurai before turning into sword form.

Nikko can take human form as seen in Kichikuou Rance. Also in Kichikuou Rance, Chaos complained that God is not fair because she can transform back to human form when he can't, even though they both wished the same wish to the God.