Ryuuzetsu was a kunoichi that appears in Naruto 5: Blood Prison. Ryuuzetsu was a childhood friend of Mui's son, Muku. Just like Maroi, she also had an undercover mission in order to investigate Mui as to the disappearance of Muku when he was still young.

Ryuuzetsu has the kekkei genkai, Ryuumei Tensei (龍命転生,Ryūmei Tensei) or Dragon Life Reincarnation, that enables her to heal or restore life in exchange for her own.

(Source: Narutopedia)