So, recently in a game I'm part of, my character did arguably the most (logical, yet) evil thing I've ever done in an RPG. I typically play fairly straight-and-narrow characters. In D&D, I often choose things like Paladins, or benevolent Wizards using their magic for the good of the people. Occasionally I go with a somewhat morally grey character, but the closest to "evil" I've really come was playing a merchant who doesn't always sell what he says he's selling (Think Jonathan from The Mummy. Sometimes he actually gets a real artifact, but most of the time he's selling you a random trinket instead). However, in my friend's Force and Destiny campaign, I decided to play a much more self-centered character. And, as a result, I have committed what I believe to be the most 'evil' action I've done in an RPG.
For context, the game is taking place just a single year after Revenge of the Sith, and most of the party members are Force users. Two were former Padawans who survived through different means. One character helped harbor Jedi after Order 66, and received some training during that time. And then there's my character, Kuroth Boone.
He's a Pau'an who was too old for the Jedi Order to take in for training when they discovered him, despite his naturally powerful affinity with the Force. He grew up a successful businessman and philanthropist, but made a bad investment shortly before the Clone Wars kicked off. He'd taken a loan from the Intergalactic Banking Clan to commission a large number of farming droids from the Techno Union. Days after the commission had been paid for, the Techno Union and Intergalactic Banking Clan took sides with the Separatists as the Clone Wars were kicked off, and the money he'd paid the Techno Union was instead used to build more Battle Droids for the war effort. The IBC raised the interest rate massively on his loan, throwing him into debt. The Republic, desperate to find people to point fingers at in their propaganda campaign, uncovered the transaction between Kuroth Boone and the Techno Union, and treated him as an enemy of the Republic. When the war ended, the IBC got absorbed by the Empire, who again raised the loan's interest rate to help fund the Imperial Navy and the various post-war efforts.
As a result of all of these unfortunate events, Kuroth Boone was forced into hiding on his home world to avoid being jailed by the Republic as a war criminal. He fostered a strong dislike for the Jedi, both for passing him up for training, and also for their role in kicking off the war that ended his career. He has been forced to liquidate all of his assets and even sell his company to try and pay off his massive debt. When he finally met up with the rest of the party, he was initially distrustful of them, due to their Jedi connections. However, after meeting with a supposed Jedi Temple Guard who has offered to train the party, Kuroth has been willing to work with the others (Mostly out of selfish goals, after learning that the temple that this Jedi Knight is guarding contains a vast wealth of extremely valuable crystals).
In the most recent game, we were on a mission to a planet that is building mining droids, with a goal of shutting down a certain company's production of droids in order to stall mining that would otherwise jeopardize the crystal caves of the Jedi Temple we're training in. When we arrived on that planet, we learned that one of the Jedi members of the party is actually a wanted criminal there, with his face on various posters in the hangar bay and around the city. Naturally, this lead to many shenanigans of trying to hide this party member while we were on this world. At the very end of the game session, that party member was finally spotted and captured. Aboard our ship. The way my character saw things, we had two options: Try and save him from the captors, who were currently our allies and the only hope we had of shutting down production of the mining droids, or claim he was a stowaway and have him taken in for the reward on his head. My character didn't hesitate for a second to sell out one of the party members.
To me, this is the most evil act I've done in an RPG. Granted, I can rationalize it all day long, and it truly is the more logical of the choices that were present at the time. The party made off with several thousand credits, the Empire would now see our party as allies and treat us more favorably, and the mission was no longer in jeopardy. But at the same time, I gave up one of the party members without a moment's hesitation (Admittedly, the player had been intending to change characters for the next game anyway, and this character was being written out of the campaign regardless).
So now I'm kinda curious, what would you say is the worst thing your characters have done in the games you've played? For the sake of discussion, let's exclude games that were intended to be evil campaigns from the get-go, as any evil actions during such a game are, by definition, pretty much a given.