I have a problem with my players being really murder-y. The goal of the campaign is a pretty good one, saving innocents from a cult. They have to explore the city to find the cult and it isn’t too difficult to figure it out. There is some options to kill people, but that makes a large impact on the story and normally has some roleplay reason (ex. one of the players is hunting down the cult to kill them because they killed sacrificed his parents who were investigating them). They have been surprisingly good people until the last session. All of them wanted to do something bad except the new player. “I am going to go and mug someone because someone pick pocketed a few coins off of me.” “I’m going to become a hired killer for a gang.” I know I made some mistakes with not expecting this as one of the players always is a psychopathic killer. I don’t except fabulous roleplay from him, but his entire backstory is that his parents died in a house fire so he became a bounty hunter. He just does whatever he finds fun or profitable. This leads to the group splitting often, making it very boring for certain members of the group to sit around while we go through combat in the bathroom. I need a solution to this problem, as the player who became a hired killer is pretty bad at it and slipped up big time. If he goes to prison, I’m not sure if the other players will care enough to help him get out. He’d probably be on death row for 4 counts of manslaughter. If he makes a new character, I think the other one will be a murderous man with no morals whatsoever.
Communication is always key. Say all these things to the player. Tell them your concerned, tell them it feels like it is taking away from the fun of the game for you as a GM. Sometimes people legitimately have no idea, and just communicating it can change things right away for the fun.
Did you sit down with the players at the start and all discuss what you wanted out of the game, and what you didn’t want in the game? If not, you might sit down and do that now, after resolving what’s happening to the character (which seems 100% reasonable that the characters wouldnt’ care and the prison guy dies or gets removed from the story).
Other suggestion is that when the party splits, don’t physically split the players, keep everyone in the same room. There is very rarely an actual good reason to keep things going on by themselves.
Last thing, you are the GM, just flat tell the player “No” when they tell you the character they want to make. Say, “That isn’t fun for me as a GM, and I don’t want to deal with it, let’s come up with a different character.”
Fun is suppose to be had by all, not just the players and the GM is left hanging. The GM too.
First rule when letting evil players join a party, they have to give a really strong motivation for why their character would join up with the rest of the party. The reason is simple, if they cant do that then their character wont have any motivation to actually follow through with the mission like the rest of the party. They will instead wander off and do random (usually counter productive) stuff. Some DMs just outright ban evil characters to prevent this from happening. I think evil can work, but the player needs to be above average in RP, because they need to come up with rationalisations for why their evil character keeps doing good things. You have it precisely backwards, if they player wants to be evil, they need to be a good RPer, you should expect more from them if they want to be evil. An evil lich wanting to track down an evil cult makes no sense, an evil lich wanting to track down the evil cult who forced him to turn undead and he isn’t happy about it, that can work.
Your mercenary doesn’t seem to have any motivation to help the party achieve their ends, and so they don’t. I suggest letting them know that if they want to play a character like that they need to give them a motivation that fits them into the story. In this case you might have to give them the motivation yourself, though since you are basically forcing it on them after the fact you should talk with them first.
He can be a bounty hunter with dead parents, but he has to have motivation beyond that. Maybe the local prince / mayor / whatever hired him and there is a big pay day in it for him, but it is cash on delivery and they wont stand for any of the nonsense his reputation brings with it. When a character is motivated by self interest then that interest must be made to align enough with everyone else to allow the story to proceed.
“I am going to go and mug someone because someone pick pocketed a few coins off me” - This strikes me as pretty questionable role play, and doesn’t really advance the story. There are options here though, maybe the person they decide to mug offers them information for not getting stabbed, information the off the rails hero wants, the identity of the person who actually pick pocketed them.
Although from the sounds of things you might have slipped up a bit here. Never have an event happen that isn’t plot related. The pick pocket needs to either be part of a side quest, or the main quest. Players should never just be randomly pick pocketed. Sure it is realistic, but it is also boring and if you are going to just do random stuff why shouldn’t your players? The pick pocket can be a member of the cult, or someone made destitute by the local gang that has ties to the cult and so on, but they need a reason for being there. With something like this it also helps if options for investigating the crime are quickly made available. Maybe the bartender knows who the local thieves are.
“I’m going to become a hired killer for a gang” - Again, how does that help track down the cult? I mean infiltrating a local gang because it might have ties to the cult, sure, but just joining a random gang?
From what I can tell the problem isn’t that your players are behaving evil, it is that they aren’t actually engaging with the plot.
Now you’ve got a fair old pickle on your hands here because things have gotten out of control. Your players are splitting the party, which is usually a bad sign, and some of them are off doing plot irrelevant things for no obvious reason while the party is split. To reign things back in I think you are going to need to have a talk with your players. You need to talk to them as a matter of priority because how you resolve the situation is going to depend on how they respond. Maybe they want to do an evil murder hobo campaign and you are okay with that. Maybe they want drastically different things and this will be impossible to resolve. Maybe they wanted to blow off some steam because combat oriented players haven’t got to stab anything in a while. You need to decide what kind of campaign you want, you need your players to understand that and be on board.
I would have a sit down with the murder-y player and tell them you have an idea to get their character a interesting motivation, because you need some plan to get yourself out of the hole, narratively speaking. My suggestion, would be to try the psychopath for murder and have him convicted. Then have the town put a curse / remote explosive / device in his head and inform him that if he doesn’t help hunt down the cult one button press / remote invocation / whatever will redecorate the nearest wall brain matter grey. Kill any more civilians and they push the button. Device to be removed on completion of the quest.
The character stays evil, but now has a reason to pursue the plot. But remember, most important thing here, talk to your players, find out what they want. Then offer them alternatives.
Put his character in prison and role play the trial. Let the other players play the defense while you play the prosecution and judge plus any witness. Also tell the player the problem. Also death penalty is definitely an option.