To authors who write RPG-style stories: I have a question. I have an idea for a story in that genre, but how do you honestly keep your protagonist from turning into a straight-up murder hobo?
Are pest exterminators fumigating a house of cockroaches considered murder hobos? How about hunters who are licensed to hunt only a specific number and type of deer because overpopulation affects trees? Like some others have said, give them a reason, and that murder hobo label mostly disappears. Everyone made good points already about any characters that kills endlessly with no social frame, no moral calibration, no consequence, and no interiority being as bland for readers' tastes as chewing on cardboard.
Wanna know something? My examples? They cost something. So give that violence a price tag. Like, maybe the act causes physical injuries, political backlash, reputation damage, some fun trauma, or even literal costs like economic repercussions. Something like if your character, or maybe a Goblin Slayer, were to wipe out a goblin camp, what were the losses? Even that lunatic accounted for what he used to perform his own version of pest control. And there have been cases where people retaliated for something as insane as killing a bunch of goblins because, who knows, maybe someone was thrilled a camp was there because it became an obstacle for a rival merchant trade route.
Since my mind is on it, social infrastructure is a key component here. Things like guilds, churches, city-states, or even those adventurer codes. Let's tap into another series, KonoSuba, because the guild there exists to bureaucratize chaos; paperwork civilizes slaughter.
Maybe since I'm now on paperwork, we can even look at the crafting or diplomatic aspects, even skip back to trades, or maybe research... OH! Hey! Territory management! Dude, look at Log Horizon's politics and economics sometime; those matter a helluva a lot as much as raids because combat in that series is like one-tenth of what those characters jump into. The first episodes of that series even revolved around the ethical code of how guilds should be ran because one veteran guild was abusing newbies for their free health potions.
So that would start getting into where the personal lines are also drawn such as refusing contracts involving children. Well, if you have a story like that, that's pretty damn dark... okay, now I got Dark Knight on my mind. Maybe instead they are someone like Batman who refuses to kill anyone, but they will beat the ever living shit out of them until they are mentally unfit for society; welcome to Arkham!
Yeah, that is another thing to consider; enemies have lives too. If every enemy is labeled a monster that evaporates into loot, that removes consequences with only gains to be had. But if you include culture, language, or even something as primordial as burial rites, that gives the character a moment to reevaluate what they are about to do; are they killing monsters, eradicating pests, or are they about to murder genuine people who have loved ones expecting them to provide for their family and kin? And if they have that depth, go back and consider the reasons they must be killed off and what happens as a result; the pros and cons.
There is a lot to consider here and plenty of examples in the RPG-style that displays characters who have to be more than just murder hobos.
Oh, one more thing: if someone here points out goblins are just monsters, not people... I believe a light-blue slime named Rimuru Tempest would like to have a word with you.