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“
I am a humble servant of Count Bleck... Master of dimensions... Pleaser of crowds... I am... Dimentio!
„
~ Dimentio introducing himself.
“
Now the Chaos Heart is mine! I will use it to destroy all worlds... And create perfect new ones! So, shall we get started? Now I have all I need... To become the king of all worlds!
„
~ Dimentio becoming Super Dimentio.
Dimentio is the main antagonist of the 2007 video game, Super Paper Mario.
He initially started out as a minion seemingly loyal to Count Bleck; however, as the game processes, he makes it clear that he plans on betraying him so that he could use the Chaos Heart for himself in order to destroy all worlds and recreate them in his own image.
Unlike his associates and employers, who have some sympathetic qualities (O'Chunks lost his army after being sold out by one of his advisers, Mimi is implied to be a failed Pixl experiment, Nastasia was once a bat that was given a human form after Bleck freed her and has developed a crush on the count, Mr. L was a brainwashed Luigi corrupted by Nastasia (and later Dimentio himself) to be the destroyer of worlds, and especially Bleck, who's painted as tragic for losing Timpani and being betrayed by his father), Dimentio has none since he's never played for sympathy, especially with how he appears to become more bloodthirsty as the story progresses and the implications that he wrote the Dark Prognosticus, the very book Bleck read that set the game's plot into motion in the first place. Also, unlike the others, he approached Bleck on his own accord and joined him from the start with the intent of eventually betraying him for his own purposes.
For this reason, he does not have a happy ending as with all the other members of Count Bleck’s crew.
In his first major encounter, he brainwashes Fracktail, an otherwise benevolent guardian of a Pure Heart to make him attack and try to eat Mario, which forces him to fight him and results in him being destroyed, all for his amusement. This is the first indication that he's truly evil.
Halfway in the game during chapter 5, he tests if a Floro Sprout (the presumed parasitic young of the Floro Sapiens) can zombify anything other than a Cragnon by implanting it in O'Chunks, who at that point is his co-minion, which temporarily turns him into a mindless vegetable.
Sends Mario, Luigi, Peach, and Bowser to the Underwhere, where the unrighteous souls of those whose "games are over" spend eternity, as part of his plan to defeat Count Bleck.
He saw Bleck's feelings for Tippi/Timpani only as a weakness to be exploited, which he did by confirming to Bleck that Tippi was indeed Timpani so that he'd be emotionally weaker by the time they arrived to stop him, and therefore, easier to defeat.
Lies to the heroes by saying he joined Bleck in order to save the day as a ploy to have them brainwashed and under his control.
He also lies that he'll give them a special power to defeat Count Bleck, when in reality, he had been planning to brainwash them with Floro Sprouts as he did with O'Chunks earlier on.
After Count Bleck loses to the heroes, he tries to finish him off in his weakened state with a magic projectile, which another of his henchmen, Nastasia, intercepts to protect him, which initially seems to mortally wound her in his place. He mocks this as by saying it was an "adorably hopeless gesture".
Once he obtains the Chaos Heart, he reveals his true colors as he intends to destroy the multiverse, meaning the murder of an unfathomable amount of lives, for the purpose of of making "perfect new ones". Even Bowser, the series main villain, is against the idea of a world getting destroyed (let alone all worlds).
Transports Count Bleck, Timpani, and Nastasia to his own dimension with the explicit intent of torturing them to death after he's finished, as shown by his declaration to Bleck that "he'll squeeze the life out of him later".
While other villains in Mario series wish to take over the world (or at least the Mushroom Kingdom), they were not willing to destroy it in order to do so. By comparison, Dimentio destroys numerous dimensions when he’s using the Chaos Heart so he can remake them to his liking. The cherry on top is that after he is defeated, instead of graciously accepting it, he plants a part of his power inside so it will destroy the multiverse as an act of spite, leading to the sacrifice of Bleck and Tippi.
Even though he has many comedic moments, they do not detract from his heinousness. In fact, in some cases they just show how sadistic he is.
Trivia
Dimentio is, along with the Shadow Queen (English), King Boo and Princess Shroob, one of four villains from the Mario franchise to be Pure Evil. He is also one of the only two Pure Evils to come from the Paper Mario series.
Dimentio is often not only considered one of, if not the most evil villain in the Super Mario Bros. franchise, but possibly the most evil villain Nintendo has ever created, or at least one of the worst, especially due to the sheer scope of his plot and the trillions it would affect, which is almost unparalleled in most of their other franchises.
His final form serves as the icon for the Spoilers template in the Pure Evil Wiki.
This is likely a reference to how his final boss form and true main antagonist role are shown to be spoilers for Super Paper Mario as well as the fact that his Pure Evil status is spoilers for Super Paper Mario.