Leo and Deo were lover gods that have been in love with each ever since they were created, and they had lived different lifetime together with no changes to their heart desires. Maybe they could have been changes to their heart desires if they didn't shared one heart, which means whatever happen to one happens to other.

However, Leo was a god with a demonic side and a good side which are the souls of his powers. The demonic side of Leo is called Fawrus, and the good side of him is called Fawmus, and they are both what owns his shared powers.

Leo's demonic side, which was Fawrus, sought to end Deo to make Leo powerful and have revenge on Deo for what Deo done to him . Fawrus felt that the death of Deo is what will make Leo achieve his true purpose and greatness, and in the process, he will release Lucifer from hell to unleash hell on Earth as intended.

However, Leo's good side, which was Fawmus, has to do everything in his powers to save Deo, since he loved Deo and wanted to stop Fawrus, which is the only way to put an end to the hell that will be unleash on Earth.

Leo himself will have to give up everything including his life to save Deo from his demonic self, and make sure she is safe for all eternity.