Мафия 39. Piece of emptiness for the small December.

He is actually useful to us.
But if you eliminate him, the mafia will attack him.

1) The mafia gets distracted.
2) The townspeople die slower.
3) An overpowered maniac is spawned.

Added after 34 seconds
And the maniac has no reason to help us, given his set of abilities and various defenses.