Kurisu is the sister of Sulik, a tribal warrior. Kurisu is a young tribal girl kidnapped by slavers. Although Sulik's quest was to find her, he never did.
The following is based on Van Buren and has not been confirmed by canon sources.
She somehow appeared many years later somewhere in the Southwest in Blackfoot Tribe. She was taken as a slave, later earned a place as a worker. She proved her worth as a skilled fighter, won her freedom and becoming the raider. When the old leader Ramon died suddenly she took over as leader in 2248.
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 cancelled 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).