Ryuuzetsu

Ryūzetsu is determined, guarded, and initially suspicious of Naruto's impulsiveness. She is nevertheless compassionate and deeply loyal to people she values.

Her lack of fear and killing intent becomes especially significant against Satori, whose predictive behavior depends on sensing those emotions.

Ryūzetsu is an accomplished ANBU operative with Fire Release training. Her unique bloodline ability allows her to perform Dragon Life Reincarnation, transferring her own life force to another person.

She is also capable in direct combat and infiltration, allowing her to survive inside Hōzuki Castle while concealing both her mission and identity.

Ryūzetsu meets Naruto Uzumaki inside Hōzuki Castle and eventually explains the history of the Box of Ultimate Bliss and Mui's missing son.

After Muku returns as Satori, Ryūzetsu continues trying to reach her childhood friend. She later shields Naruto from a fatal attack and, after Naruto defeats Satori, uses Dragon Life Reincarnation to restore Naruto's life at the cost of her own.

Muku is Ryūzetsu's childhood friend and the person whose disappearance motivates her investigation. Mui is Muku's father and the target she initially intends to stop.

Naruto Uzumaki becomes Ryūzetsu's closest ally in the prison, while Maroi temporarily cooperates with her against the conspiracy surrounding the box.