Seven Guardians of Light

The seven guardians of light (7光の守護者), is a group nominally consisting of seven Keyblade wielders that is first referenced in Kingdom Hearts 3D: Dream Drop Distance.

Kingdom Hearts 3D: Dream Drop Distance
Following their sealing of the seven Sleeping Keyholes, Sora and Riku both end up in The World That Never Was. While the former is put into a deep slumber by Xemnas, Xigbar, and Young Xehanort, Riku escapes from within Sora's dreams and arrives in the true world. Reaching the castle and meeting up with King Mickey, Riku faces Young Xehanort before the other members of the real Organization XIII appear and taunt the heroes. Master Xehanort then reveals his plans to them; while he had originally attempted to create the χ-blade and summon Kingdom Hearts using Ventus and Vanitas, this was not the proper method. Instead, a clash between thirteen hearts of darkness and seven hearts of light would create the χ-blade and allow Xehanort to more properly accomplish his goals. He then states that, should the heroes want to protect the seven Princesses of Heart, they would need to gather seven guardians of light to defend the princesses and face the darkness.

Mickey hypothesizes that the guardians could include himself, Sora, Riku, and his three lost friends (Terra, Aqua, and Ventus), but cannot think of a seventh. Xehanort then contradicts this count, claiming that Sora and Terra, who he refers to as "another on your list", belong to the Organization. Just as Xehanort prepares to send a piece of his heart into Sora to create the thirteenth vessel, Lea arrives to help the heroes escape, later joined by Donald and Goofy. Having been thwarted from claiming Sora, Xehanort tasks both groups with filling in their numbers before they meet again as destined.

Later, after Riku rescues Sora from the Armored Ventus Nightmare, Lea reveals that he had been training to use a Keyblade, and surprisingly manages to summon his Keyblade, Flame Liberator, as he speaks. Yen Sid then tells Riku to bring Kairi to him, where he declares her to be another guardian of light.

Kingdom Hearts III
Yen Sid sends both Lea and Kairi to Merlin, where the two were trained in order to join the guardians of light and be able to battle against the real Organization XIII in equal footing. Meanwhile, both Riku and Mickey seeks out a way to rescue Aqua from the Realm of Darkness, while Sora travels to other worlds in order to regain his lost strength. In time, he joins Riku and Mickey as the former battles against Anti-Aqua, and succeeds in expunging the dark influence from Aqua and rescuing her from the dark realm. Aqua and Sora then head to Castle Oblivion, which is then reverted back into the Land of Departure by Aqua, to retrieve and awaken Ventus. However, their efforts are halted by Vanitas, who seeks to take Ventus's heart for himself. While Aqua fends off the dark warrior, Sora is able to use the power of waking to restore Ventus's heart to his body, prompting an outnumbered Vanitas flees. Lea and Kairi finish their training around the same time, allowing the Seven Guardians of Light to be properly convened and reunited with old friends. Donald Duck and Goofy, despite their lack of Keyblades, are also dubbed Guardians of Light.

The Guardians of Light head for the Keyblade Graveyard the next day, greeted by Master Xehanort, Young Xehanort, Ansem, Xemnas, and Vanitas, who send a large wave of Heartless, Nobodies and Unversed to wear them down. Despite overcoming the army of creatures, the Guardians are confronted by Terra-Xehanort, who intends to extract their hearts by force. While Ventus and Lea are knocked out by him, Donald manages to repel their foe by channeling all his stamina into a Zettaflare spell. However, a Demon Tide appears and swallows all the Guardians into the Final World for the Lich to take their hearts. Sora manages to hang on thanks to Kairi's belief in him and restores himself, saving his friends. The Guardians once again face Terra-Xehanort, who is repelled by the Lingering Will. Xigbar and Dark Riku unleash a new wave of Nobodies, Unversed and Heartless to wear down the Guardians. However, Yen Sid arrives and uses a wall of light to create a path for the Guardians to head after the Organization, though Donald and Goofy stay behind to back-up Yen Sid.

Confronting the Organization at the crossroad of Keyblades, the Guardians watch as Xehanort summons a labyrinth from the depths of the ground to serve as the arena for the final battle. In the ensuing battles, Dark Riku is extracted from his replica by the Riku Replica of the present, leaving a vessel for Naminé's hear; Xion's present day heart inside Sora takes control of the replica inhabited by her past self; Roxas is revived, after sensing his friends in danger, inhabiting a replica Vexen prepared for him; and Kairi is kidnapped by Xemnas. The One Behind turns on Terra-Xehanort, revealing itself as the vessel of Terra's heart. Sora helps restore Terra to normal, who then takes Kairi's place in the group.

Master Xehanort reveals that all the clashes have forged twelve Keyblades and one more clash will create the thirteenth and final one needed to create the X-blade. Ruthlessly slaying Kairi, Master Xehanort enrages Sora into clashing with him, creating the thirteenth Keyblade, which fuses with the others to become the X-blade. Xehanort summons Kingdom Hearts to begin his plan, but the arrival of the others guardians gives Riku an idea; they can trap Xehanort within himself to stop him. While the King, Riku, Lea, Roxas, Xion, Terra, Ventus and Aqua hold off Kingdom Hearts, Sora is joined by Donald and Goofy in sealing Xehanort. This drags them to his soul world, Scala ad Caelum, where the defeat the Replica Xehanorts and Master Xehanort himself in several battles. As Xehanort declares his victory, the other guardians arrive, explaining Kingdom Hearts is closing. The lost heart of Eraqus appears from Terra, convincing Xehanort to admit defeat. Xehanort gives the X-blade to Sora and departs to the afterlife with his friend. With everyone's help, Sora seals Kingdom Hearts for good, returning everyone to the Keyblade Graveyard and finishing the Seven Guardians of Light's role. However, Sora uses the power of waking one last time to look for Kairi, rescuing her at the cost of fading away.

Members

 * Sora: A boy from Destiny Islands which has the ability to wield the Keyblade. With the help of friends he's saved the world several times.
 * Riku: Sora's best friend and a Keyblade Master.
 * Mickey: The king of Disney Castle and a Keyblade Master.
 * Lea: Human form of Axel and one of the new Keyblade wielders under Master Yen Sid and Merlin.
 * Kairi: A Princess of Heart and one of the new Keyblade wielders under Master Yen Sid and Merlin.
 * Aqua: One of Eraqus's students and a Keyblade Master who was brought back from the Realm of Darkness by Sora, Riku, and Mickey.
 * Ventus: One of Eraqus's students who was brought back from his sleep by Sora's Power of Waking.
 * Terra: One of Eraqus's students. Initially a member of the real Organization XIII as Terra-Xehanort's vessel, he manages to regain control of his body with the help of Sora. After Lea's Flame Liberator is broken by Xemnas, Terra takes his spot as a guardian of light during the final battle.
 * Roxas: Sora's Nobody and a member of the first Organization XIII. With the help of Ienzo, Vexen, and others, Roxas manages to obtain a vessel for his heart and becomes a guardian of light during the final battle, fighting in Kairi's place after she is taken by Xemnas.