|Home world:||Earth (Neo Frontier Space Timeline)|
|First appearance:||The Closed Amusement Park|
|Last appearance:||Ultraman Dyna: The Return of Hanejiro|
|Number of appearances||TBA|
|Family||Tetsuo Shinjoh (older brother)|
Takuma Aoki (fiancé, decreased)
|Portrayed by||Kei Ishibashi|
She works as a nurse in TPC. While in a flight returned to Japan to prepare for the Japanese Grand Prix and meet her, Takuma Aoki, her fiancé and a motorcycle racer, is killed by Gazort II in 15th episode. Takuma's soul returns to help Daigo and Shinjoh distract Gazort II in order to give them time enough to hide away from the monster. Meanwhile, Daigo transforms to Ultraman Tiga to fight and destroyed Gazort II. In the end, his soul gives Mayumi the necklace with her's picture, which Takuma hold in his hands even the death is nearby, and tells Mayumi he always love her before departing to afterlife. She joined the organization with the help of her older brother, and she sometimes has great sibling-type arguments with him.
In Ultraman Dyna, she was promoted to the rank of Head Nurse of the TPC.