Saïx

“	Yes...I know. You wouldn't do that. But...I was jealous.	„
	~ Saix admitting to Lea he let his jealousy get the better of him when referring to his friendship with Roxas and Xion

“	Humanity is a precious gift. And yet you desire to return to the Organization?	„
	~ Saix to Vexen

Saïx, the Luna Diviner, is one of the secondary antagonists in the Kingdom Hearts series. He is the seventh member of the original Organization XIII and a member of the new Organization. He wields a claymore and the power of the Moon, using the latter to enter a berserk rage. He commands the Berserker nobodies. He is the Nobody of Isa who is Lea's best friend.

Despite being an antagonist however, Saïx (alongside Demyx) served as an anti-hero in Kingdom Hearts III although he was apart of Master Xehanort's thirteen seekers of darkness he secretly plotted against him as he seeked to atone for his past misdeeds as he was the driving force of bringing Roxas and Xion back despite mistreating them while in Organization XIII as well as make amends with his best friend Lea. He met Even (Vexen's somebody) to recruit him back into Organization to gain access to the replica program to find a way to bring Roxas, Xion and Naminé indirectly helping Lea in his ultimate goal of brining his friends back, the latter seeking to atone as well agrees and later recruits Demyx to help them in their plot against Xehanort, as a result he indirectly protects Lea and Xion from getting killed by Xemnas in the final battle by having Roxas rescue them in time.

He is voiced by Ginpei Sato in Japanese, and by Kirk Thornton in English, who also voiced Kevin Ryman of the Outbreak Survivors in Resident Evil: Outbreak.

History

Kingdom Hearts III

Following the Organization's failure to turn Sora into a vessel, Master Xehanort, Xigbar, and Saïx meet at the Keyblade Graveyard to find a way to complete the Organization. Saïx, having discovered Vexen's notes on the forgotten Xion, suggests using her to replace Sora, and decides to fetch Vexen to refine the replicas. Visiting Radiant Garden, Saïx approaches Even, who is wandering the square, with an offer to rejoin the Organization. At the Keyblade Graveyard, Vexen lies that he chose to return to the Organization to continue research on his Replica Program, with Saïx saying Ansem did not appreciate his abilities while Xehanort did. Saïx would the begin to work with Vexen to atone for his past misdeeds against Roxas and Axel.

Saïx later appears at the Clock Tower in Twilight Town with Lea, but with no intention of fighting him. The two talk as if they were still friends, their conversation revealing their true motives for joining the original Organization XIII; as Somebodies, they had befriended a girl only referred to as Subject X, who was held inside the castle of Radiant Garden. When she disappeared, the two became apprentices of Ansem the Wise before he too disappeared and Isa became a Nobody alongside Lea. Their entire reason for climbing the ranks of Organization XIII was to get information on Subject X and learn what happened to her, knowing full well that Xemnas, as Xehanort's Nobody, has knowledge of her predicament, but they had no luck in finding her. Saïx's anger at Axel's newfound friendship with Roxas and Xion was out of betrayal, feeling Axel had decided to forget about Subject X. Lea rebuffs, trying to persuade Saïx to leave the new Organization, but Saïx retorts by saying Roxas is gone forever too. Saïx and Lea part ways fully expecting to battle one another at the fated place.

Later, Saïx and Xion confront Kairi and Lea at the Keyblade Graveyard, with Saïx subtly trying to jog Xion's memories by calling Lea, "Axel" several times, however when Saïx mentions Roxas it causes her to attack Lea and Kairi before Sora's arrival. Saïx overpowers Lea, who once again tries to persuade his old friend to stop, until Xemnas arrives and berates Lea for his treason. Saïx simply watches as Xemnas mercilessly attacks both Lea and Xion before Roxas arrives to save them. Xemnas kidnaps Kairi, leaving Saïx to deal with their enemies. Sora, Roxas, and Xion fight and defeat Saïx. When Lea approaches Saïx, the latter asks why he looks sad. Lea responds by commenting on what the Organization has reduced Saïx to. Saïx once again reminds Lea of his betrayal, not to the Organization, but to him, as he befriended Roxas and Xion while abandoning their goals after everything Saïx had done to try and find her. Lea assures him he never forgot, which Saïx knew deep down, allowing his jealousy to get the better of him. He fades away in Lea's arms, being called by his real name before being reborn as his original self.

Through a Secret Report, it was revealed he was actually a key part of the Guardians of Light's victory; having met Even, both expressed a desire to atone for their past actions. Since Saïx was already in the real Organization XIII, he had the ability to bring Even in as a Nobody once again, the latter willing to sacrifice his new life to get access to his Replica Program, which would allow Roxas, Xion, and Naminé to become human and therefore coexist with their original selves. Interestingly, by doing this he (and Vexen) indirectly assisted in Lea in achieving his goal of finding a way to bring his friends back.

Sometime after in the game's epilogue Isa is reborn as his original self and reunites with Lea, Roxas and Xion on top of Twilight Tower hands out sea-salt ice cream and are joined by Hayner, Pence and Olette and together they join the others at Destiny Islands for a celebration, Isa and the others bear witness to Sora and Kairi reuniting one last time before the former disappears for misusing the power of waking.