Demon King Reincarnated in The Realm of Angels

Lie xeung the Demon King was once a mortal during his mortal life. His parents always pestered him to get a job and do something with his life. One day, he fell fast asleep due to fatigue and awoke during a war. Although,he didn't think it was legit the first thing that came to his mind was It's just a dream then he tried to wake up but then the opposing threats stabbed his hand then he knew it was for real. Lie xeung referred to as the demon King was now powerless and killed and the Angels were victorious. As the demon King lay down with his last breath he shouted "Reincarnate". Then our protagonist woke up again but what shocked him the most was that he was in the mists of Angels. What do you think our protagonist is going to do.. Will he Avenge his people as the demon King or live a free and simple life as an Unknown species of the Angels.