Kurisu is a young tribal girl kidnapped by slavers. She is also the sister of Sulik, a tribal warrior. Although Sulik's quest was to find her, he never did. She somehow appeared many years later somewhere in the Southwest and became leader of the Blackfoot tribe.
Kurisu was first mentioned in Fallout 2, but was not given a name. She was initially meant to be found in the game, but this quest was eventually unfinished and Kurisu was cut from the final version.
She also was to appear in Black Isle's canceled Fallout 3 project (Van Buren) as a joinable ally. Her name was revealed in the Van Buren leaks (it is a joke concerning Avellone's first name, her name being 'Chris' with Japanese pronunciation). It is not certain if she will appear in any future Fallout game.