Franchise: Mario

According to Nintendo via a Nintendo Direct "Year of Luigi" announcement, Mario and Luigi are twins. It's also been stated that Luigi is the youngest.

A tech demo developed by Shigeru Miyamoto over a number of years titled "Mario 128" was shown off at Nintendo's Spaceworld 2000 trade show and was designed to showcase the GameCube's ability to utilize multiple AIs. The demo featured 128 Marios dismantling a pseudo-8 bit Mario sprite composed of several blocks by picking up and carrying them away. This project had a tumultuous development cycle with little to no details coming out over the years until 2007 when he revealed at a GDC Keynote that some parts of the project were utilized in two games he produced in the 2000s. The general concept and some other parts of Mario 128 were developed into Pikmin after Miyamoto asked his team to create an entirely new game that would be nothing like a sequel to a Mario game. As for the second game, the ability to warp the terrain seen in the tech demo as well as "different sizes of spherical items" influenced the free-form gravity and ability to walk around entire planets in Super Mario Galaxy.

On the cover of Super Mario Bros 3 Mario's overalls are different compared to Super Mario Bros 2. Instead of having a blue sweater, and red overalls, it was changed to be blue overalls, and red sweater. It has stayed the same ever since.

An issue of Nintendo Power revealed that Shigeru Miyamoto got the idea for Boos from the wife of his co-worker and close friend Takashi Tezuka, as she is shy but one day got very angry at him for coming home late from work. Boos were also originally named "Boo Diddleys" after the late blues singer and guitarist "Bo Diddley".

According to series creator Shigeru Miyamoto, Mario's appearance was the result of graphical limitations in the original Donkey Kong: his overalls allowed his arms to be visible against his body (as there was no room for outlines), his hat substituted for hair and eyebrows (and did not need to be animated when he jumped), and the large nose and mustache made up for the lack of space to depict a mouth.

Miyamoto additionally stated that the design was influenced by the decision to make Mario Italian-American, identifying his large nose in particular as a distinctly western feature.

According to Shigeru Miyamoto, the Koopalings aren't actually Bowser's children, despite the Super Mario Bros. 3 manual stating that they were.

Shigeru Miyamoto wanted Mario to have a dinosaur companion ever since Super Mario Bros. but it wasn't thought possible at the time due to the limitations of the NES. He wanted to implement Yoshi in Super Mario Bros. 3 but again could not. Two power-ups were created to fill the gap - raccoon and frog Mario. Co-worker Takashi Tezuka once speculated that Miyamoto's love of horse riding had influenced Yoshi's creation.

According to Mario Bros. developer Takashi Tezuka, there was a stage in Super Mario World's development when Yoshi was a Koopa. A relic of this idea is Yoshi's shell-like saddle.

Shigeru Miyamoto had originally intended for Bowser to be an ox, and based him on the main antagonist from the animation "Alakazam The Great". This is likely why his modern design has horns and a defined muzzle, despite him being a turtle.

There is a pornographic parody film released in two parts based on Mario called "Super Hornio Brothers". Nintendo purchased the rights to the movies following their release to make sure they would never be released again.

Mario was not Mario's original name, and nor was Jumpman. When Miyamoto created the prototype of Mario, he called him "Mr. Video" and planned to put the character into many games (possibly as cameos, as he did with Mario). But even before then Mario was called "Ossan" which means middle-aged guy.