I've just noticed an interesting development, at least in my games anyway.

As we all know, Kagemusha is so far the only mafioso to successfully eliminate all the villagers in my games. He accomplished this feat in Mafia I.

Ever since then, every time Kage has died, things start to go bad for the mafia. In Mafia II, he was killed by Cowhead. Very soon the suspicions start falling on Lemur. In Mafia III he is Wrath of Godded and shortly after the mafia collapse. In Mafia IV he is executed in the first round. The next two people to be executed are the two mafiosi.

I think there's a curse of some sort that whenever Kage dies, things start to go wrong for the mafia. This is probably just superstition, but you can put it in the glossary if you want.