Mamiya is a character from Fist of the North Star. The leader of a village, she bears a resemblance to Kenshiro's fiancee Yuria. Mamiya hires Kenshiro and Rei to protect her village from the Fang Clan. However, the Fang Clan manage to capture her brother Kou, her last remaining relative, and she is forced to allow the clan to kill him, as the alternative was allowing the village to be sacked. She subsequently assists Kenshiro and Rei in their effort to find the Fang Clan hideout and eliminate them once and for all.
Mamiya subsequently helps Kenshiro find Toki, learning that he's being held prisoner in Cassandra.
On Mamiya's twentieth birthday, she was kidnapped by Yuda, a practitioner of Nanto Seiken with a demented obsession with beauty, and who also killed her parents before her eyes. While Yuda's captive, she was branded with his signature "UD" insignia on her shoulder, but managed to escape and returned to her village three days later. She chose at that point to give up her womanhood to become a warrior.
After Rei is doomed to die in three days by Raoh's strike to one of his pressure points, Rei learns that Mamiya too is cursed by the Death Omen Star and also learns of her past with Yuda. Having fallen in love with Mamiya, Rei pledges a vow to end her suffering and dedicates what little time he has left to tracking down Yuda and killing him.
To respect Rei's last wishes, Mamiya gives up her life as a warrior and embraces her womanhood.
Mamiya later appears during the Gento arc, in which her village comes under attack by an officer of the Celestial Imperial Army that wishes to draw out Kenshiro. It is revealed that since Ken-Oh's defeat, she and Airi had been living quietly in the village for years prior to the arrival of the Celestial Imperial Army.
She makes her last appearance during the final arc of the manga.