Xavier

Xavier is a Demon. During the late Nighcisa era, Xavier was sent to JAPAN to defeat Fujiwara Ishimaru. Afterwards Xavier was sealed by a monk from JAPAN. He has since broken the seal and revived a few times, but had been resealed everytime.

In the early LP era, part of the seal was broken, and he took possession of Oda Nobunaga's body while seeking to break the other seals so he could fully revive. He succeeds in doing so according to the canonical storyline and tries to take over Japan. Failing this, he tries to sink Japan into the abyss by destroying the Tenma bridge that connects JAPAN to the main continent and keeps is afloat. However, he is eventually defeated and killed by Rance, commanding the Oda army. His soul is afterwards annihilated for good by Miki, the demon king.

In Kenshin IF route, He was forced out of Oda Nobunaga body