My Senior Brother Is Really a Demon King

Li Haoxuan shouldered the mission and was reborn in an era before the immortal fate was opened, in order to prevent the soul-eating demon from seizing the body and becoming a saint. He originally planned to find a corner and stay there until the fairy fate comes back again. Until one day, his master was very restless and took in another junior sister for him... He just discovered... He unexpectedly traveled through time and became the Demon King himself!