Mushoku Tensei: Jobless Reincarnation (Light Novel) Vol. 4

Continuing their journey, Rudeus, Eris and Ruijerd have a run in with a figure from legend--none other than the Great Emperor of the Demon World, Kishirika herself! When the trio lend her their aid, Kishrika rewards Rudy with a strange new power...one that might just be more than he bargained for.