
spoiler (be aware that i didn't read the novel but read the spoilers from novelupdates)
long story short, everybody dies. Dion goes crazy after learning the truth about their bet, and decides to take revenge from everyone who ruined his life (he literally kills everyone including the humans). He awakens as a hero and completes his revenge by killing the demon king. After that he kills himself too and while dying he talks with the 'death' and death tells him he has a lots of karma because of how many people he killed. Dion says he would pay up his sins and his brother's karma too. Death takes his eyes as a punishment and he reincarnates as a blind and ill-fated in his every life so his suffering never ends ig there is a sequel too but idk
i couldn't resist and read the spoilers of the novel and let me tell you, it only gets worse lmao