Make a Good Level X and X2 have created many original characters and developed existing ones due to the nature of the contest. Some of the most memorable include
Umbra Noctis "Aim Sure Pro" TenebraeA cool dude with a cooler 'tude, one meme-y character created by Cooldog in the level "Demonic Gathering". The baddest a** of the Mushroom Kingdom. In the Improved Hub version of the first contest, Umbra joins the crew on various exploits in existing levels, in bonus "Umbra Missions".
- Anti-Hero: He's trying to stop Bowser's demonic gathering in his first appearance, but he is constantly edgy and hates the police.
- "Awesome McCool" Name: Just look at it!
- Catchphrase: Several. The best ones include: "Pig$$$", "Cop$$$", "you're a real piece of pie huh?" (but never to an actual pie) and "cheese to meet you, smell head".
- Cool Guns: See Improperly Placed Firearms below.
- Department of Redundancy Department: When the various words in his name are translated from Latin to English, the name turns out to be "Shadow Night 'Aim Sure Pro' Darkness".
- Improperly Placed Firearms: Umbra is noted for using several real life guns (or at least butchered versions of), not something a Toad or any Super Mario character would normally do.
- Rouge Angles of Satin: He apparently wields the "Dessert Eagle" as one of his guns.
DisgruntledgammlerThe very angry face of Talkhaus user Jolpengammler. Ever since his first appearance in a joke level, Versus Disgruntledgammler, in the first contest, he's become a recurring joke in the series.
- Marathon Boss: His original fight, a three-phase fight, each phase of which requires ten hits each from very slow bomb spawners. And a constant flow of Rinkas, on top of that.
- Recurring Boss: Has appeared in a multitude of levels since his first appearance, such as "The Plot", "I Read in a Book That In Talkhaus, Savannahs are More Like Keeps", and "Ma GLX Redux".
ForozeOriginating from the Super Mario Bros. X episode "Apocalypse of Foroze", Foroze has become a recurring joke character in multiple levels. His most notable appearances are in "Do You Remember raocow's Apocalypse of Foroze LP? Yeah, This Is Like That" and "The Plot" from the first contest, and "Mario and Foroze Hang Out" in the second contest.
- Enemy Mine: Mario and Foroze team up in "Mario and Foroze Hang Out" to take down Ignoritus and stop him from nuking the ship to get rid of Valterri. Foroze lied, though. Ignoritus was actually powering the ship with dance powers the whole time.
- Friendly Enemy: He's pretty friendly in "Mario and Foroze Hang Out", because he's on vacation. The most evil thing he does besides blowing up the ship is making an elevator really slow.
- Go-Karting with Bowser: In "Mario and Foroze Hang Out", Mario and Foroze read fanfiction in a closed-off room that Bowser trapped them in for four hours. Foroze teleports both of them out, but only after he's finished the entire fanfiction.
- The Dragon: To Justice Man.
- Out-of-Character Moment: In "Horikawa's Not Done Yet", Foroze talks like Mike from Startropics.
Justice ManOriginating from Mega Man Rock Force, Justice Man first appeared in "The Plot", as the ultimate mastermind behind everything.
- Luke, I Am Your Father: Is revealed to be the brother of Mario and Luigi in the end.
- The Man Behind the Man: Supposedly was behind everything in the first contest.
ZbambabarOriginating from "Super Talking Time Bros 2", he is the "creepy Kirby" that has made minor appearances in the series. In the first contest, he appeared Dreamland's River of the Damned (a hell-like level), stating that he was from there. In the second contest, he appears in two levels: "Spike Castle" (a castle full of spike hazards) as a cameo, and "Well Shucks, I Never Expected King Dedede to Be So Deserted" (a Womb Level where you get to go inside of Dedede) as a bigger role. He has weirded raocow out in all of his appearances.
- Eldritch Abomination: Implied to be one in Dreamland's River of the Damned, where he says he's from there (basically Hell).
- In-Series Nickname: True to his character, he still calls the player character "Unca Weegee" (so far only Mario and Luigi have encountered him in a playthrough).
- Shapeshifting: Strangely enough, he can transform into multiple things, including nerve cells.
- Shout-Out: In "Spike Castle" of MAGLX2, he says he "saw (implied to have defeated Needle Man too) Needle Man note , but he was nothing compared to Majin Buu".
Super Mario Bros X 2.0 NewcomersIn the third tier of the postgame, there were 8 levels that introduced a pleasant surprise. They were new characters that were going to be coded for Super Mario Bros X 2.0, and each level introduced a new character. These characters (in order) are Rosalina, Ninja Bomberman, Wario, Bowser, Snake, Zelda, Mega Man, and Samus.
- Unexpected Character: A lot of these characters are unexpected, especially Ninja Bomberman and Snake.