"The only reason a DM rolls dice is for the sound they make."
"Rule Zero: The GM is always right."...but sometimes, he's our cheating bastard. While Video Games are run by a cold, inhuman computer, Tabletop Games can be more flexible because they spring from the mind of living, breathing Game Master (who may or may not be cold and inhuman.) The Random Number God's power can be broken, plot-devices can appear to save or bedevil the players, encounters can suddenly become harder or easier and, depending on whether or not the game is Serious Business, in-jokes can abound. There are even specialty "Dungeon Master's Dice," which are more-or-less the same... but blank on every face! This can be a blessing if the players want to send their adventure screaming Off the Rails or eschew the usual Fighter, Mage, Thief party structure for something more flavorful. A nice cheating bastard can make sure things stay fun for the newbies and maybe give the characters a little help when they've had a run of bad rolls. Unlike that bastard, the computer, a good GM will mainly fudge the rules to preserve the vastly more important Rule of Fun and Rule of Cool. However, this trope has a dark side. If the nice GM takes things too far, the players' victories can seem preordained and hollow. And Pelor help you if a Killer Game Master is a cheating bastard... you might run up against a band of omniscient orcs that fight like they were trained as Spetsnaz. A sudden Ass Pull might save his Villain Sue, or you could miss a twenty-foot-long dragon because you Failed a Spot Check. If a particular player gets annoying, his/her character might get a Pit Fiend dropped on them. (Hell, the entire party may fall victim to falling rocks if the GM's feeling especially vindictive.) And remember those blank dice? A computer can't feel spite (as far as we know), but you may yet come to miss the Random Number God. But take heart! It can be nice to Earn Your Happy Ending, and it certainly feels good to have your characters triumph in this GM's mad world. It can often be more fun to be killed by this GM than to survive the entire adventure of a GM that's too nice.
- Irregular Webcomic! references this here. (The characters are in a Deep-Immersion Gaming situation, so it makes sense in that context.)
- In the Dexter's Laboratory episode "D&DD", we see Dexter as a Killer Game Master, cheating at dice rolls and throwing badly unbalanced encounters at his party for the express intent of "winning".
- Penny Arcade explores this relatively frequently, sarcastically (how else would they do things?) suggesting supreme vindictiveness on the part of those GMs. How? Magic. Magic doesn't work like that? MAGIC .
- The rules of the parody RPG Hol explicitly state that the "HoLmeister" is allowed to cheat whenever he wants to. Period.
- This is also the case with Paranoia, to the point that GM Fiat is a listed equipment type.
- The infamous "Dungeon of Dorks" sketch (you know, "I'm attacking the darkness") has the Dungeon Master eventually reveal that he fudged a roll to avoid killing a player character whose player showed admirable gumption.
- In Spoony's Campaign, during one battle where Skitch's character Garret is downed and fails a death saving throw, Spoony fudges it in order to make up for an unexplained AC penalty that came up (and was apparently a glitch in the character builder program). Or at least he tried, but Skitch was kind of spacing out and missed what was happening, causing Spoony to rescind his charity.
- Sword Art Online has two examples.
- Akihiko Kayaba, who became a Killer Game Master when he trapped all the players in SAO, had their avatars permanently deleted on death, and also killed players who died in-game in the real world. He appears in-game as Knights of the Blood Oath guildmaster Heathcliff, using his administrative privileges to keep himself alive long enough to be the eventual traitorous Final Boss. Subverted in his last duel with Kirito, though, when he did away with his GM advantages (he was good even without help from the system) and accepted his defeat with elegance.
- Nobuyuki Sugou, a Corrupt Corporate Executive who traps the minds of many SAO players after that game is cleared for Mind Control experiments and is GM of Alfheim Online. When Kirito reunites with Asuna, he uses his GM privileges to use an unreleased, overpowered spell to bind them and modify Kirito's pain absorbers while torturing him. He is ultimately defeated when Kayaba's virtual ghost allows Kirito to use his administrative privileges and pull this trope on Sugou.
- Destroy the Godmodder: Due to the meta nature of the game, the fact that this is one of its founding tropes is lampshaded every once in a while by characters. The best part is that its revealed in-universe that some of the characters are aware of their own fictionality, even after the point in the second main game when the game master is pulled into the game and a good number of the players decide to get revenge.
- And then amped up when Doc Scratch kills twinbuilder (the GM at the time) and takes over the game temporarily, abusing his GM powers, even up to the point where he becomes a boss.note
- Nimble in The Gamers is basically able to change the rules of the game at will. His antics include Back Stabbing a powerful enemy with a ballista, and Retconning his own death three times.
Nimble: "Did I say walk down the corridor? I meant sneak down the corridor."
Nimble: "Did I say sneak down the corridor? ...I crawl down the corridor. Inch by inch. Looking for traps."
Nimble: [To Rogar, the party tank] "OK, actually, you go first."