Michelle

Michelle is a strong member of FUCKS who was part of a group of "friends" years ago, including Jeff and Donut.

Season 2
Jeff explains to Brigade his connection with Rob, saying that the two of them, and Donut, were all friends when they were younger. Rob interrupts and says that Jeff left someone out, but Jeff disregards the comment and changes the subject. Shortly after, Rob mentions the fourth person again, who is revealed to be a girl named Michelle. Michelle appears behind Brigade and Jeff, huge in size, and knocks them out.

Season 3
As Jeff stares into the sky, alone after killing Donut, Michelle appears from behind. Jeff doesn't turn around. Michelle reveals that the one who unlocked the cells that were holding Jeff and Brigade in the FUCKS HQ was, and that she also unlocked the room that Donut was trapped in. Jeff continues to have his back to her, ignoring her. Michelle questions him about why he's doing what he's doing, and Jeff simply responds finally by turning around and firing his gun rapidly, shooting Michelle several times and killing her.

Fifteen years in the past, a younger Michelle walks up to a recently beaten up Andro to tell him about someone named Mr. P who spoke to her. Andro asks about who this guy is and what he wanted, and Michelle whispers something into Andro's ear, which causes Andro to become enraged.