Sonchou is out.
I think Envy hate him because I think Envy fought against Hoenheim many times because of the relationship b/t his mistress and Hoenheim.
Maybe, Hoenheim kicked Envy's ass many times.
I have funny theory.
From preview for 45, I realize that Dante might have a feeling for Hoenheim or used to have a feeling for him. And, Maybe, Envy liked his mistress.
So, this relationship might caused the classic love triangle fight.
Or, Envy might be Hoenheim's brother or son.
Who died and revived by Hoenheim, and failed.
that might be why Envy hates Hoenheim and Ed so much.
It is my personal theory.