Gene Wolfe 
Wizard [EPUB ebook] 

THE WIZARD KNIGHT springs from the myths, legends and literature of times past. A teenager passes from Earth to a magical realm of seven worlds, where he is given a hero’s adult body and named Able. Though forced to act as a man, inside he is still a boy, even as he sets off to find his destined sword and become a knight. In his quest he battles giants, meets gods, heroes and a sorceress (who repeatedly tries to seduce him), and serves the mercurial dragon king Arnthor in a was that could end everything.