I fail to see how that works in Obi's favor cookie...
Judging by the role I would say Obi is unaligned so it isn't really that the mafias want to keep him alive, it is that Obi wants the mafias to keep him alive... He is essentially the mafias bitch unless he doesn't wish to win.
Sounds pretty crappy actually when you think about it 0_0
Lol... Obi = mafia's bitch
edit:
Correction: Actually not only the mafias bitch, really anyone who has the power to kill can force Obi to carry out their dirty work or you know, they can kill Obi...