The only way I was able to get my PCs to behave and not KILL 'EM ALL was to (sorta) railroad them into a situation in which they had to stop hackan' and slashan'. That situation was one in which they were up against a giant army that they couldn't possibly kill themselves, so they had to seek out allies.
They bullied the leaders of like a half-dozen tribal villages into providing them with troops, which they used as a meat shield so that they could strike at the leaders of the army. The "bullying" RP sessions were awesome, I had no idea that my players could be so creatively sadistic.
So.. I guess. Put them up against something they can't do themselves, and make them seek help. Make it a door with some enchantments on it, so they've got to speak to a high level wizard in order to open it. Have one of the PCs get captured if they go on stupid rampages, and the only way to prevent their execution is with some HARDCORE DIPLOMACY TIEM. Do something like that.
The only reason they're hacking and slashing is because that's probably all that you've had them do.
>>3067278I remember when he was filling the board up with his faggotry about how he wanted a sister, which made me hate him. However, if other fa/tg/uys say he's redeemed himself, than I forgive him as well.