Yeah, thats heavely implied, we know he was the guy in the auction house, so he is involved with the macrosa (⊙…⊙ )
It's heavily implied, almost confirmed. He was the one at the auction house and him asking FL while in disguise to be his Queen was in reference to the macrosa Queen since he would be blowing his cover if he casually asked a woman to be his Queen as in marrying him. Also the hidden underworld bosses are usually the characters who wear the bubbly/kind personality mask, and we see their switch to true self in a scene where Mc cannot see them. It's 99% true.
Arma's the macrose king I think. Hopefully not.