Jaden who was tortured by everyone he knew in every way possible,died. Adair, the Head most feared leader of the military and the powerful human king of the underworld also a S-level mercenary known as A, died too. However, he woke up ending up in weak Jaden's body while he was being rejected by his mates. He swore to help Jaden get his revenge, but Adair had to get his revenge on the person who betrayed him first. Find out how human Adair tries to fit into the supernatural world and how will he get his revenge?.