Mushroom King

The Mushroom King (also referred to as King Toadstool or just Toadstool in the Nintendo Comics System) is a seldom-seen ruler of the Mushroom Kingdom, and the father of Princess Toadstool. Although he is said to rule alongside the princess, he is a figure that is absent in the video game series. He does make somewhat notable appearances in other early media such as the Nintendo Comics System, Nintendo Adventure Books, and the Asian-drawn strategy guide illustrations for Super Mario Bros.. He is also mentioned on Princess Toadstool's profile in a 1993 character guide produced by Nintendo of America.

Super Mario Bros.
In the NES instruction booklet of Super Mario Bros., the Mushroom King is briefly mentioned in passing. With few exceptions such as Super Mario Bros. Deluxe, this is generally not included in subsequent releases as the Japanese manual does not mention him. 1987's The Official Nintendo Player's Guide mentions that he ruled the kingdom with a queen. Although unmentioned in either the games themselves or the manual for Super Mario Bros, he was mentioned in the Japanese guidebook How to win at Super Mario Bros..

Nintendo Comics System
In the Nintendo Comics System, the Mushroom King is the de jure leader of the Mushroom Kingdom. However, he is depicted as scatterbrained and dimwitted, so his responsible daughter often performs his royal duties as de facto ruler in his stead. Wooster, the "chief mushroom assistant" and the king's personal subject, is occasionally at odds with him due to his lack of intelligence.

Based on his role, it is likely that he was based off the kings from Super Mario Bros. 3 as he plays a similar role in the comic strips (having a magic wand that is often taken by Bowser's forces and being transformed into various animals). One story also implied that he is frequently kidnapped by Wart.

Nintendo Adventure Books
The Mushroom King appears in most of the Nintendo Adventure Books, continued from his depiction in the Nintendo Comics System.

Super Mario (Kodansha manga)
The king appears in the Super Mario Kart arc of the Super Mario manga which stretches from volumes 15 to 17. After Mario and Luigi accidentally break one of his items while on the job, he sponsors a tournament with the winner being made king for a day. Mario ends up winning the cup but has to do a mountain of paperwork for a day.

The king returns in the Super Mario Land 2: 6 Golden Coins adaptation, specifically in volumes 20 and 21. Princess Peach calls him with her cell phone, and he comes to pick her and Mario up in his royal submarine, but the submarine gets smashed by a giant hammer held by the octopus. After escaping from a whale, the king joins Mario and friends in their renewed quest to saving Mario Land. Near the end of the arc, Wario's dark power influences the king's subjects to stage a coup and hijack a missile to destroy Mario's castle so no one can have it. Upon Wario's defeat, the subjects regain their senses.