According to producer Kensuke Tanabe around the game's release, Nintendo placed stricter guidelines on the Paper Mario series beginning with Paper Mario: Sticker Star. Tanabe previously mentioned these guidelines in a 2012 Iwata Asks interview for the latter game, stating it was originally a directive from series creator Shigeru Miyamoto. Under these rules, developer Intelligent Systems was no longer permitted to significantly visually modify existing Mario species through aspects such as age or gender, or introduce entirely new characters that expanded the broader Mario setting. As a result, they could no longer create distinctive versions of familiar species, such as uniquely-designed Toads, Goombas, or Bob-ombs with unusual body shapes and appearances, in the same style seen in the first two Paper Mario titles, although for Paper Mario: The Origami King, they were allowed to design different clothing and accessories for Toads. These restrictions also retroactively applied to older side characters and party members introduced before Sticker Star, prohibiting their return while the guidelines remained enforced (this presumably does not affect remakes as evidenced by the 2024 remake of Paper Mario: The Thousand-Year Door). Tanabe's 2020 comments on this restriction angered players who suspected that Nintendo had been exercising stricter creative control over the wider Mario series' character designs, a trend colloquially called the "Mario mandate", not helped by the hundreds of collectible, nearly-identical Toad NPC characters in The Origami King.