Killing is easy in the moral vacuum of videogames. So when Daniel Mullins needed a challenge, he gave peace a chance.

Mr. Mullins, 19, is the creator of "Felix the Peaceful Monk"—his character in a videogame called "The Elder Scrolls V: Skyrim." The game gives players wide latitude over their on-screen characters' appearance and actions. Felix, who is half man, half cat, has become a small-time Internet celebrity for his steadfast refusal to kill.

In videogame excerpts Mr. Mullins has posted on YouTube, Felix roams an icy fantasy world doing things like soothing angry wolves with magic. In one video, he explains how to turn away threatening skeletons, noting Felix won't even harm the undead. And when an assassin tried to gut Felix with a knife? While most players have swords and arrows for would-be hit men, Mr. Mullins hit his with a calm spell.
[Pacifist]

Felix the Peaceful Monk

"Apparently someone wants me dead. But that doesn't mean [the assassin] deserves to die," Mr. Mullins explains.

Videogames have long been assailed for their violent themes and gruesome imagery. But a small slice of players has embraced a new strategy: not killing. They are imparting real-world morals on their virtual-world characters and completing entire games on a "pacifist run"—the term for beating a blood-and-guts adventure without drawing any blood.

The cool restraint of pacifism can bring bragging rights and even a taste of online fame. Videogame enthusiasts routinely post videos of their accomplishments on YouTube.

Kotaku, a videogame blog, has done posts on a handful of pacifists, including one who conquered the post-apocalyptic world of "Fallout: New Vegas" without taking a single virtual life. A number of violent videogames award virtual "trophies" to anyone who can complete the game without killing.

Stephen Totilo, Kotaku's editor in chief, says videogame pacifism isn't usually a moral decision but rather "an urge to break the rules"—and dial up the difficulty of the game. "One of the most interesting challenges is to get through the game without killing," he says.

Virtual pacifism can be a squishy concept. Ian Jones, a 21-year-old college student in Charlotte, N.C., has also been playing Skyrim as a "pacifist." But his method is hardly nonviolent: He uses spells to possess the game's computer-generated bystanders, and they do the killing.

Tweaking the rules to make a game more difficult is as old as play itself. Some golfers, for instance, challenge themselves by playing with one club instead of 14.

In the 1980s, enterprising videogame players used to try to get through Nintendo's "Super Mario Brothers" without squishing the orb-like enemies encountered along the way—just to see if it could be done.

Today, many videogames involve complex fictional worlds and give players free rein to create and shape characters—including the chance to mold their moral compass. In the Skyrim game, players can slay dragons or plunder tombs, but also get married or do tasks like chop firewood or cook.

When an enemy comes along, a player can take the obvious route: Pull out their sword and hack away. But they can also sidestep conflict with peaceful methods such as spells that make enemies friendly (albeit temporarily) or simply run away.

Todd Howard, who directed the team of developers who made the game, notes killing isn't the only morality test. "Many [players] won't steal," he says.

On his first run through Skyrim, Mr. Mullins took a more traditional path: He built an avatar that was obsessed with fire and went around torching people. The character engaged in cannibalism and acquired a valuable artifact by killing a priest with a rusty mace.

When he was sufficiently sickened, Mr. Mullins sought redemption in a new peace-loving avatar: Felix.

"I really wanted a change of pace," says Mr. Mullins, who goes to college in Kingston, Ontario.

DeeAnna Soicher isn't all that comforted by the idea that a subset of videogame players are merely choosing to play as pacifists. Her 16-year-old son, Brock, is an avid fan of videogames, despite attempts by Mrs. Soicher and her husband, Drew, to keep him away from them.

Brock's first videogame system came connected to a treadmill. Worried that videogames would turn him into a couch potato, the parents' stipulation was their son could only play when the treadmill was moving.

Today, after wearing down his parents with wit and good grades, Brock has a PlayStation 3 that he plays on a denim beanbag chair in the basement. The double zeros in his online identity, BrockyBoi00, come from an old football jersey that hangs framed above the television.

But Mr. and Mrs. Soicher still don't want any violent titles in their suburban Denver home. Brock can't have any game that has a rating above "T" (Teen). Recently, when Mrs. Soicher found a copy of a shooting game called "Kill Zone," she laid it on the kitchen counter so Brock would know he'd been busted.

Thus, she was pleasantly surprised to learn Brock posted an online video for how to complete a "death match" in the game "Uncharted 3: Drake's Deception"—but without actually killing anyone. Brock's method, as explained in a voice-over in his online tutorial, was to climb away from opponents and hide along a rafter.

"Given what a 16-year-old boy could be putting on YouTube, this is fine with me," says Mrs. Soicher.

Brock was inspired by Mr. Mullins's YouTube videos (the two have never met, online or otherwise). He doesn't have a problem with violent games, as videos of his other adventures can attest. Still, he wanted to make the point that games should have more nonviolent options.

"I guess not killing in videogames is rebellious," Brock says.

He recently created a new video of him playing "Battlefield 3," the sort of realistic war game his mother usually forbids. Instead of killing, however, Brock's on-screen character goes around reviving enemies with a defibrillator. The song he picked out: A cover of the Edwin Starr classic, "War," which includes the famous line: "What is it good for? Absolutely nothing."