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Icon-den-o.pngThis article is about an ally in Kamen Rider Den-O.

Mai (マイ) is the mother of Anna. In 1989, she went by the nickname Melon (メロン, Meron) by her friends.[1]



Mai is a little girl in 4th grade when she meets with Anna who tries to run away from Momotaros who she thinks is an evil pervert monster. Mai pretends to be be a karate 5th dan and tries to confront Momotaros, just realizing he looks monstruous. Mai succeeds to run away with Anna, where she gets the surname of Melon-chan. They also both learn that they're extremely similar. When arriving in front of their school, she realizes that Anna comes from 30 years in the future.

After Momotaros' quiz, Mai shows and gives Anna her "treasure", a Heisei New Era lottery winning bill. Shocker comes back in the Den-Liner and succeeds to take Mai in hostage. However, Momotaros possesses Anna and both transform into Kamen Rider Pretty Den-O to save Mai. After the battle against Ika Devil, they retrieve the bill however cut in half. They repair it with some adhesive tape, but Anna prefers giving it back to Mai, because Anna's real treasure is her friendship with her. Both girls greet each other when Anna had to go back to 2020.


Around 30 years after the battle against Ika Devil, Mai is now around 40 years old. When she asked her daughter Anna that before leaving the house she needed to tidy her room, as not done a previous time, Anna ran away. After a little while, she finds her daughter where she threw the lucky charm. Kamen Rider Den-O: Pretty Den-O Appears!

Behind the scenes


Mai is portrayed by Otoha (乙葉). As her younger self, she is protrayed by Tsugu Sasaki (佐々木 告, Sasaki Tsugu)



Icon-den-o.png Kamen Rider Den-O
Kamen Riders
Ryotaro Nogami - Yuto Sakurai - Past Man - Kotaro - Kotaro Nogami - Gaoh - Negataros - Ghost Imagin - Shiro - Kuchihiko - Mimihiko - Reiji Kurosaki - Eve - Anna
Transformation Devices
Den-O Belt - Rider Pass - K-Taros - Zeronos Belt - Zeronos Cards - New Den-O Belt - Gaoh Belt - Yuuki Belt - Golden Khakkhara - Pure Silver Metal Stick - G Den-O Belt
DenGasher - DenKamen Sword - ZeroGasher - Denebick Buster - DenGasher (New Den-O) - GaohGasher - Nega DenGasher - Momotarosword - Uratarod - Kintaros Ax - Ryuvolver - Ghost Imagin's sword - Shiro's Whip - Shiro's tops - SavageGasher - Golden Khakkhara - Pure Silver Metal Stick - DenGasher (G Den-O)
Rider Machines
Machine Den-Bird - Machine ZeroHorn - Machine GaohStriker - Machine Nega DenBird - Machine New Den-Bird
Time Transports
DenLiner - ZeroLiner - KingLiner - New DenLiner - GaohLiner - Nega DenLiner - Ghost Train - Battleship of Oni
The Ally Imagin and the Support Characters
The Taros: Momotaros - Urataros - Kintaros - Ryutaros

Other: Sieg - Deneb - Teddy - Futaros

DenLiner: Owner - Naomi - Hana - Stationmaster
Milk Dipper: Airi Nogami - Seigi Ozaki - Isse Miura
The Imagin
Contract holders
Kai - Death Imagin
Bat Imagin - Chameleon Imagin - Crust Imagin - Crow Imagin - Rhino Imagin - Ivy Imagin - Owl Imagin - Whale Imagin - Wolf Imagin - Jelly Imagin - Tortoise Imagin - Scorpion Imagin - Spider Imagin - Bloodsucker Imagin - Molech Imagin - Cobra Imagin - Salamander Imagin - Gecko Imagin - Newt Imagin - Wasp Imagin - Bluebird Imagin - Rabbit Imagin - Anthopper Imagin - Kraken Imagin - Mole Imagin - Leo Imagin - Pandarabbit Imagin - Snail Imagin - Oct Imagin - Armadillo Imagin - Albinoleo Imagin - Snowman Imagin - New Mole Imagin - Pink Rabbit Imagin - Clown Imagin - Ghost Imagin - Phantom Imagin - Shadow Imagin - Piggies Imagin - Mantis Imagin

Other: Gelnewt