Airi, Rei's younger sister, faced violent disruption during her wedding preparations when Jagi—a Hokuto brother marked by seven chest scars—invaded her home. He murdered her parents and abducted her. Enslaved and traumatized by witnessed horrors, Airi deliberately poured poison into her eyes, blinding herself permanently as psychological escape.

The Fang Clan held Airi captive, using her to manipulate Rei. Their leader forced Rei and Kenshiro into a duel for her safety. With Kenshiro's aid, Rei rescued her. Kenshiro then restored her vision using Hokuto Shinken pressure points, allowing her to see Rei again and cementing Rei's trust.

Airi's resolve shifted after witnessing Lin's bravery against Ken-Oh's invading forces. Inspired, she transformed from victim to defender, arming herself with a crossbow to protect Mamiya’s Village and kill several soldiers. This marked her evolution into an independent fighter.

Following Rei's death battling Ken-Oh's forces, Airi remained in Mamiya’s Village to tend his grave and honor his legacy. Rei Gaiden notes her later stay in Asgarzul before her return. She reappears in the sequel series, continuing as guardian of her brother's memory.

In the 1986 film, Jagi personally enslaved Airi, and her blindness resulted from seeing his disfigured face. Kenshiro and Rei still rescued her, but Lin restored her vision. Airi does not reappear post-rescue. Video games like *Fist of the North Star: Ken’s Rage* and *Hokuto ga Gotoku* reiterate her core arc—abduction, blinding, rescue, transformation—integrating her into gameplay without altering her fundamental story.