GASLIGHT DISTRICT THEORY
My theory is that Ken attempted to do the exact plan Mel made (break into heaven, steal the human egg, and kill it), but was there a bit too late and Mel had already hatched. He was then caught by the virtues, and that's how he got sent to the inferno
We know that he escaped, so I think that when he escaped, he took Mel in an attempt to still salvage his plan and try to kill her, but in the end couldn't bring himself to do it since she was a helpless baby at the time, and so he took her in as an adoptive daughter
And THAT was why he got sent to the inferno AND why he was so hesitant about Mel's plan at the start. Because he already tried it, and it made him have to conceal the fact Mel was human















