Sword of Dawn

Gawain crossed, but something went wrong when he crossed.
After floating in the sky of a certain foreign continent for 10,000+ years, he felt that he might need a body to become a complete traveler, but he did not expect that he would need to bring this body with him after finally succeeding. Crawl out of the coffin and face two terrified great-great-great-great-granddaughters.
And a world that is approaching the end of an era.