Sword of Dawnbreaker

During Gawain transmigration, a little problem occurs.
After hovering in the sky above the land of a strange world for over hundreds of thousands of years, he realizes that perhaps his transmigration is completed by acquiring a physical body.
Never did he imagine that he would have to guide the body out of a coffin after going through great difficulties to obtain it, only to come face-to-face with his two extremely shocked great-great-great-great… great-granddaughters, and also—
Be thrust into a world that’s the verge of its era’s end.