Cast Out, Returned as Their Doom

DramaBox synopsis

Forced to take his brother’s place and die in war, Jerome Gray returns three years later as a half-step Heaven Realm Martial God. His family steals his credit and breaks off his engagement. Having had enough, he cuts ties with them. He startles everyone at Oswin Academy with his unmatched skill and gains powerful allies. But when a demon dragon invades, the family that cast him out begs him for help again.