I find that, Like Lily Caul killing Brian Blake (Who we didn't know about Lily until she kills Lori/Judith, and she kills him for revenge) I think that Mark will kill him.
Rick WILL join the saviors and he, Molly, Carson, Savior 17, Savior 18, Paul, Mark, Sherry and Amber plus a released Jesus will decide to overthrow/kill Negan like the animals in Animal Farm (sorry, I am reading it). More saviors will join as well. They also join up with Dwight, but there mutiny is lost when Dwight betrays them. Negan slays carson and a few other saviors and is about to kill Jesus when on savior close to Negan is stabbed by a spear. Kal, Eduardo, Gregory, Samuel, Wes and many others (including resident 1 and others) will attack the saviors as well as Andrea, Carl, Maggie, Michonne, Eugene, Aaron, Eric, Heath, Holly, Nicholas, and Spencer attack at a flank. Mark grabs a gun admits the confusion and hits Negan in the side of his face with an iron. As he cries in pain, Mark shoots him. Eduardo and Nicholas are hurt while Samuel dies and Eric is shot and killed by Tara/John. Dwight gets killed by Holly as she screams, "For Abraham", and Paul (savior) is stabbed by Mike. Maggie kills a few, Carl kills alot and Rick shoots multiple wanderes as they break through. Jesus kills Tara as well. Mark and Amber are left unknown because they stay behind, while most of the other saviors run back, but are also unknown. A few saviors agree to come back, as well as Mike and Sherry. An undead Paul attcks the group and bites Spencer, so Andrea amputates his hand.