Doppelgangers

The dopplegangers are a race of evil clones from the Reverse Dimension, they constantly try to attack the heroes and wind up being defeated, but come back because of the Dark Star X, however, MM54321 merged it safely with the Light Star X, causing both to return to their old form, Star X, and the doppels were sent to the unstable Dimension X.
== History ==
The Doppelgangers originated in the Reverse Dimension, a dimension where people are evil. After some time, OiramOiram12345, the doppelgänger of MarioMario54321, was sent to the Mushroom Kingdom to search for a source of immortality. During the events of the video game, Mario and Luigi: Bowser's Inside Story, OO wound up trapped in Bowser's body, where a large amount of important people, including Mario and Luigi, were stuck in. After learning about the Dark Star, which was being used by Fawful at the time, OO tried to steal it until he discovered the Dark Star X. Because of it's power, he choose to steal it instead.
Traveling back to the Reverse Dimension, the Dark Star X became a counterpart native there due to a law surrounding the dimension, and as such, the Light Star X was born. After that, OO went back in time with his group, the Time Crime, and merged the two star entities into Star X after a battle with MarioMario54321's Time Police, and locked the star in battle. Later, Star X was hit by a comet that destroyed it, causing the two to separate. The Light Star X then flew off and created the Light Star, and the Dark Star X flew off and created the Dark Star, (which is a paradox, as the Dark Star X was made from the Dark Star itself), and a war broke out, with doppelgangers being sent off during the era. Warrior X later found the Light Star X and the Light Star, and defeated the Dark Star X.
Hundreds of years later, the Dark Star X re-emerged, and began sending doppels after the heroes of the Mushroom Kingdom. Mario, Luigi and MM try to defeat them, but they kept coming back somehow, and nobody knew how except the villain who indirectly caused the war, Fawful. Fawful told the heroes that the Dark Star X did, but the footage was cut and everyone forgot. Later, when Luigi's doppel, Igiul, returned, MM showed the footage of Fawful explaining to reveal who D, the being who revives them, is. The Dark Star X then sends out multiple doppels against the Youtubers living in the Mushroom Kingdom, until the heroes managed to break into Hell after defeating Dark Bowser, and find the doppels lair. The Dark Star X then took over the world, knocking everybody out but the doppels, Mario, MM and CandyCao7, who are all chosen ones for who can control the Dark Star X and Light Star X.
Mario then finds Geminon, from The Cosmic Crystals IV, and after a battle between the two on the the latter's remark, and the two then exchange words, revealing the fight was a test for if Mario could use the Light Star. After having gotten the star, Mario used it to wake everybody up. After that, they broke into the castle, and after a fight with the doppels that resulted in the first floor of the castle being captured, and began fighting through X counterparts of bosses from the normal areas the castle's paintings can travel to, then left for an adventure on Ztarragus's Island X, leaving few heroes to keep the castle half they used safe when Dark Lily took over Lily. When the heroes returned, they saved Lily from her nemesis and fought more doppels throughout the X Boss counterparts based off the bosses from TCC IV, including Zythurvian X, then the Cookie King X, and then Geminon X, who was Warrior X, to be rewarded with the Light Star X, and proceeded to confront the Dark Star X.
Meanwhile, OO has created a plan to merge the DSX and his own counterpart together to destroy the multiverse, and attempted that. However it was stopped by Starman3, who separated the two X Stars from merging, and the doppels retreat, merging the Dark Star X, OO, Dark Bowser, Bowser X and the combined power of the dopples together into Dark Bowser X, to kill the heroes, causing an explosion. The explosion launched the heroes outside to panic, but Mario goes fighting Dark Bowser X, and after a long battle, Mario was killed, however, they forgot Mario was immortal with the rest of them, and attacked.
Dark Bowser X, having been tossed into two bombs, was close to defeat, but then he ordered the other dopples to destroy the other bombs, leaving Mario with no way to win, or so it seemed. MM then reveals the Fire Flower X, which Mario uses to win.
Mario and Luigi then fight the Dark Star X, who separated himself from Dark Bowser X, but Mario and Luigi win. Then Fawful comes in and steals the DSX, but gets defeated, and Dark Bowser X explodes, being who Fawful battled the bros inside of, and OO came, but before anything else, he merges with both Dark Stars into OiramOiram12345 X. So MM took the Light Star X and its normal counterpart, and merged with them into MarioMario54321 X, and the two fight until MM stabilizes the DSX, causing the dopples to fade with the X world and are sent to Dimension X, but Ztarman3, who unregistered himself, fled and created an army of dark beings known as the Blooper Stoppers, and attacked the YouTube Rangers, but was defeated by Starman3. They now live in Dimension X, with lives similar to the YTR.