Summary:

Maou and Emi duel for the last time, Emi wins and so Maou loses his powers and ends up becoming a human

Now that he is a human, he accepts Chiho's feelings, saying that while he was a demon he couldn't be with her, but now they stay together

He also rejects Suzuno.

The new info is as follows, Maou also tells Emi that he loves her, in which he says that the 3 are together, Emi asks if Chiho is ok with that, to which she says:

"I will not give up the first place, but in exchange for having this space, I allow you to have as many wives as you want, just like the Demon King from other worlds".

Result: Chiho is the main wife, but he also stays with Emi.