Otto was born in 1452. He was the youngest child of the esteemed Apocalypse family, and was constantly locked up in the estate. Otto is shown to be obsessed with Kallen Kaslana. He only tried to find the cure for the Black Plague because he thought she would been disappointed in him if he didn't. His only goal is to revive Kallen no matter the cost. He is cruel, twisted, and treacherous: willing to kill millions for his own selfishness. He is the source of many of the problems present in other characters' lives.

Otto could only watch as his plan to save his best friend killed her instead. He ran away by boat on his own and didn't come back for 14 years. During this time period, he established St. Michael's Abbey: an orphanage meant to teach the ways of 'The Holy Maid' (Kallen). These children would be his final gambit. They held Stigmata, which would help turn the tide when he came back in 1491 to overthrow his older siblings. He and his army were successful, and he was crowned Overseer of Schicksal. Otto felt empty inside. This victory would've been what Kallen wanted -- but it was far too late. She was gone.

This unsatisfied feeling began his long journey to try and revive her.

CN Voice Reference: https://www.youtube.com/watch?v=yyH1PavLkAA