RPGs that are optionally pacifist?

Not an RPG, but in the Thief series the hardest difficulty usually means that you aren't allowed to kill anyone. Many people even try to play the games as a ghost. Meaning the only sign of their presence after leaving is the stuff they stole. Every door has to be closed and locked again. Keys stolen from guards have to be returned (in lieu of a game mechanic for this you have to lay it on the ground behind them).

People do challenge runs of the Gothic games as pacifists. So it isn't part of the games but doable with some shenanigans.

Nobody would wish harm upon an innocent cardboard box

The Deus Ex series often have pacificist playthroughs (3rd one definitely does, you can play a pacificist playthrough of the OG game with a few exceptions).

The Age of Decadence has a mostly skill check and conversation playthrough. I forget if it's fully pacifict though.

Disco Elysium? More or less entirely conversation-driven RPG about an alcoholic cop who drunk himself to submission so hard he forgot who he is, hence developing him back with skillpoints. Off the top of my head there's like one combat situation which you can talk around if you're so inclined.

Otherwise, it's been said many times that "Planetscape: Torment" is similar .... ish. Not the setting, but mechanics, apparently you can entirely go through the game without combat - but that's not to say there's not going to be bodies - or so I've been told, haven't played the game to completion, only dabbled the beginnings.

So, these suggestions are with grain of salt, obvs. But afaik both are pretty high up on the rpg shelf.

Dishonored can be completed 100% pacifist, IIRC

Disco Elysium can totally be pacifist

Live a Live's Twilight of Edo Japan chapter gives a special completion reward if you complete it with zero kills, or a full 100 kills. It's designed in such a way that figuring out how to do the pacifist run is a puzzle you are unlikely to solve on your first playthrough.

This mechanic was actually one of the inspirations for Undertale!

Baldur's gate 3 has only a few required kills for main story progression. Most combat can be avoided.

Not an RPG, but: In the Hitman series, you will have to kill the target, but how many non targets you kill/cleverly avoid killing is up to you.

I believe it's possible in Cyberpunk 2077. Blunt weapons are non-fatal, other weapons can be modified to be non-fatal, stealth is usually an option, and you can even remotely disable enemies if your hacking skill is high enough.

There are sections you can't do alone, so you might need to be proactive about neutralising enemies before your companion does.

I think Disco Elysium might be the game you're looking for!

It's been a while and I've never tried a 100% pacifist run, but I think that it's theoretically possible in Planescape: Torment (Steam, GoG).

I know for a fact that the vast majority of encounters can be skipped with dialogue, and in fact, it's heavily incentivized because the combat system is not very good.

Kingdom Come: Deliverance has an achievement for a main quest line pacifist run. There is one NPC you have to kill for story reasons which apparently doesn't count towards that achievement.

In Nethack, you can fully complete the game as a pacifist, although it's VERY hard and the game is already hard to get into to begin with. In that case, you are only allowed to indirectly kill enemies by having your pet(s) kill them or by using spells which make enemies attack themselves. Or simply by avoiding enemies completely. Playing as a healer or wizard is the easiest option, but still very hard. The game rewards this and other conducts (= supported "challenges") by mentioning it in the very end after you've ascended.

I think the Of Loathing games can be pacifist

There are lots of games where combat is not even an option, like Life is Strange, Before your eyes (do play this one with a camera and a box of tissues nearby), or Firewatch. But games where you're expected to fight but can find ways around it the first example that comes to mind is Metal Gear Solid 3, you can beat that game without killing anyone, there's even an achievement for that and one of the bosses will be particularly easy if you go this route.

I mean... Kinda Baldurs Gate 3, especially if you are a high charisma class. You can also be monk. They key is dont use attack spells, and knock everyone out instead of killing them on thr mandatory fights. SO MANY of the fights in that game can be avoided or skipped with dialogue. You can, for example, bluff your way entirely into the enemy bases, use their shops, and completely decide to stay out of conflicts. Again, like you said in NV, sometimes the 'pacifist' routr makes you feel like shit. Like, you can skip having to side with either Minthara or the tieflings in act 1 simply by leaving for act 2. A lot of people die in the background though.

Only mandatory fights I think are at the end of act 2, and the final boss fight. Everything else can be avoided or conversationally skipped. In the final fight, depending on allies you got throughout the game you can technically have them fight everyone. Or you can just stealth past everything with greater invisibility or as monk or rogues that can sprint really fast.

Iirc, Deus Ex: Mankind Divided can be completed as a pacifist - and you get an achievement for that.

All Dishonored games feel amazing when you manage to get in and out completely unseen and unheard. And there's always a none lethal option to get rid of your target. Although I'd argue most of the times the non-lethal option is the more cruel one...

While Skyrim probably has the same issues you ran into with Fallout/other TES games, it's quite viable to roleplay the game without doing the main quest without the game feeling empty.

I did one "playthrough" as an Orc blacksmith, with the goal being maxing out the smithing skill and crafting a dragonbone armour to present to a chieftan of one of the orc strongholds in order to join. I started out hunting deer and making leather stuff to gen enough money for food and board, working my way up, eventually venturing into dwemer ruins to gather metal. I did a handful of quests if they felt doable for a non-heroic regular dude and ran if I got into too much danger.

Strict pacifism wasn't my goal, I was just playing as a non-heroic normal person, but I'm sure you could do something similar. You just need to abandon the main quest and set your own goal.

Most games require killing the end boss to finish the game, how exactly would you play around that? Or do you mean don't kill anyone who doesn't try to kill you?

Technically speaking Far Cry 5 meets this definition. At the beginning of the game the big bad guy arrests you and says to wait while he brings you the person you're trying to save. If you sit there for 10 minutes doing nothing he returns with the person and lets both of you go. Most people just start murdering instead

Well, Fallout 1 definitely allows it, and I don't believe necessitates unethical behavior in order to achieve. It's just a challenging and rewarding questline that I wish more games would emulate.

Sil (specifically Sil-Q, the most modern fork) is a great Tolkien-esque roguelike in the vein of Angband where pacifism is a first-class citizen. You get a lot of XP just by observing hostiles from the shadows. I highly recommend it!

You end up doing things that would (IMHO) be more fucked up ethically

Example?

I think your best bet would be looking into the CRPG subgenre, though I can't name any specific examples of games with pacifist routes.

I tried a run like that in New Vegas. I think I got to Primm, and just kept getting tore up too much to be fun.

Some of my friends and I in a D&D campaign managed to talk our way out of so many encounters, and heist our way through so many quests, that we started calling ourselves Ocean’s Five. It was some of the most fun I’ve had in that game, improving our way through heists and getting away with it.

Not sure if you can count it as a RPG, but Undertalencan be completed "normally" and with a pacifist run and also with a genocide run.

Fairly certain the NPC in Morrowind could theoretically be killed by a combination of his own drain health spell reflected back at him and/or - once he’s out of magicka - dying to fire shield.