Mafia 30. Yakuza Clans war.

I don't believe that the third note was actually written by the red Oyabun, because in that case, he should have received a modkill, and besides, a note revealing someone's role wouldn't be approved. However, the fact that there are currently 5 people in the blue mafia is quite possible... :(

Added 2 minutes later
Yes, Arandor certainly knows how many people he has in the mafia. :) For now, Vote to execute Arandor.