Saix

Saïx (サイクス, Saikusu), also known as the "Luna Diviner" (月に舞う魔人, Tsuki ni Mau Majin, lit. "Devil Dancing in the Moon"), is a Nobody with an X-shaped facial scar who can assume a berserker state of mind by using moonlight. Wielding a claymore called Lunatic (ルナティック, Runatikku), he commands the Beserker Nobodies who wield weapons similar to his. His original self is named Isa (アイザ, Aiza), a resident of Radiant Garden and a former friend of Lea's, Axel's original self. Saïx joins the Organization around the same time as Axel but, lacking the care-free personality and morals his original self had, uses Axel to become Xemnas' second in command, and feels betrayed when Axel befriends Roxas, putting his plan to get leverage over Xemnas on hold. Saïx appears completely void of emotion and completely embraces his status as a Nobody, yet continually reflects on previously having a heart. The character's Japanese voice actor is Ginpei Sato, while the English voice is provided by Kirk Thornton.
During Kingdom Hearts: 358/2 Days, Saïx assigns missions to the other Organization members. He is also assigned by Xemnas to oversee the progress of Xion, and is the one to discover Marluxia's plans to betray the Organization with Larxene, sending Axel to eliminate them. Towards the end of the game, he attacks Roxas when he attempts to leave the Organization, only to lose to the younger Nobody. In Kingdom Hearts II, Saïx appears before Sora in Twilight Town to stir unrest in him by warning him of Axel's intention to turn him into a Heartless. He later appears after Sora defeats the Heartless army at Hollow Bastion, where he explains Sora's purpose in the Organization's plans, and reveals to him that the Organization are holding Kairi hostage, Saïx having kidnapped her from Axel earlier, to ensure Sora keeps destroying Heartless for them. Saïx fights Sora on the latter's climb through the Castle That Never Was, using the moonlight from Kingdom Hearts to assume a beserker state, but Sora defeats him and he fades into darkness while pining for Kingdom Hearts to give him his heart back.^[7] Saïx's defeat led to the return of Isa in Kingdom Hearts 3D: Dream Drop Distance, where he becomes a member of Master Xehanort's new Organization.