
I suspect that Aaron is part of a separated branch of Mik's group (Yuri?) which has business in the Eastern European countries. I don't know if Mik's is trying to gain something from the mess or trying to protect his own group. Who is the man who was sent in the hospital to kill Sudou? Someone from Aaron's group or even one of Asami's men? (⊙…⊙ )

Aaron tried to kill sudoh when the police pointed at the warehouse, and sakazaki said to sudoh that his partner are ruthless men and they will try to get rid of him if there is a mishap, and asami know that but he didn't care about sudoh ! asami is the kind to kill for purpose what he will gain if he kill sudoh ? nothing ! the others are different they are afraid that he will turn them to the police!

Well that's what I meant by 10 volumes. Story Arcs don't cross between volumes. So one more story arc of maybe two volumes, just like Pray in Abyss.
Well, that is if Pray in Abyss is indeed finished. I just imagine them getting out of the roof in the last chapter could be a nice transition to a new one. Though she could very well be intending of finishing the story with this one arc name and just make it extra long.
Honestly 10 volumes seems like a nice ending point, double the volumes of what she first intended back when she was writing the Hong Kong Arc. And the final volume coming out on the 20th anniversary.
return to the main story, it was sakazaki who sold the information to mitarai , then saved sudoh and then introduce him to the one who paid sakazak, mikhael his biggest customer ! while other was trying to kill sudoh! oh it's complicated!!! we know that the politician has business with easten european mafia ! milhael is the kind of an intruder he try to gain something wherever and whenever there are troubles like a hyena ! so I believe mikhael is not Aaron boss, he is not under his command !