What is the objective of the mafia? To get rid of the town. They do this by killing.

What does the mafia do after they are dead, and have admitted it? They create confusion. Go read through past games and see what dead mafia have done to confuse the town. Why would ATPG defend YLC? To create confusion. Is he defending a scum buddy? Is he trying to make it look like he is? I'm pretty sure its the latter.

Who says the roles have to make sense? I was a canabalistic rune carver in one game.