Board Thread:Questions and Answers/@comment-25942629-20170512220605/@comment-31734791-20170808041822

He thinks that if he dies then maybe the apocalypse can be ended. To do so he experimented on Seraphs, demons, humans and anything else he could get his hands on to create his own death. He also left clues and fragments of knowledge and power around the world so he could have more variability to increase the eventual probability of creating something that could kill him. People like Mahiru and Guren, Ferid, Krul Tepes they used these fragments and ended up causing the Apocalypse to initiate which was part of his plan as it called down more Seraphs  for him to use. Shigama Goji is part of himself that he somehow created to serve as his observer and possible catalyst to his demise. All part of God's plan is to have him fall and be sent down as a test to humanity.