|“You aren't supposed to think Nikki's cool, I'm the one who has a crush on her! I mean, what?”|
|—Mason, on a reply to a letter|
|Date of Birth||July 12th, 1999|
|Species / Type||Mii|
|Vulnerable to||Call of Duty|
Mason is a Mii appearing in Nintendo Swapnote letters. He is the avatar of Mariothemovie (Talk) and is often recognized as it. He appears as the star of Mason in the Leetverse, as well as the creator of Leet in Mason's World.
- He makes his first appearance in MTM's Hair, complaining about how every Mii pretty much uses the same hair.
- He appears again in a reply to the first NoseBonerShipping letter, saying how disgusting it is.
- He once more appears in a reply of the WaluigixNikki letter, complaining about how jealous he is that Nikki would ask out Waluigi instead of him.
- Mason appears in every Mason in the Leetverse letter, getting sent to the Leetverse and going on adventures with Nine and Nikki.
- Mason appears in YoshiEgg and Crossovers, just being confused about why Tucker hates Crossovers.
- He appears in a reply to Space Prom, Part 1, showing how he has a crush on Nikki.
- Mason reappears in Nikki Poster, looking at his poster of Nikki on his wall.
- Mason appears in Parts 1, 2, 8, 9, 10, and 13 of Leet in Mason's World, and sends Leet into Mason's World, annoyed by his every action.
- Mason appears in Parts 1, 2, 4, 7, and 14 of Fantendo:Swapnote/Fantendo Life, pretty much just living life like everyone else is.