Seven Guardians of Light

The Seven Guardians of Light, or "The Seven Lights" is small group of Keyblade wielders who are destined to oppose the Thirteen Darknesses and create the χ-blade in the process.

Story
During Dream Drop Distance, Master Xehanort revealed that he knew his attempts to create χ-blade through the reunion of Ventus and Vanitas was a hasty attempt due to his impatience and that he had always been searching for a true way to forge it. For this reason he enticed Maleficent into capturing the Princesses of Heart, with his Heartless Ansem overseeing her progress, while his Nobody Xemnas created Organization XIII so his splintered selves could obtain the Lights and Darknesses, respectively. But, as Ansem failed to possess Riku and Roxas returned to Sora, Xehanort's new organization would be one member short so he decided to use Sora.

As Xehanort explained his plan to Mickey, in order to make sure the Seven Lights formed, Mickey hypothesizes that the current candidates for this role would be himself, Sora, Riku, Terra, Ventus, Aqua, and another he didn't mention out loud as he realized who the Thirteen Darknesses were. Xehanort explains that while the King was right, Terra was unavailable as he was his vessel and Sora was about to become the Thirteenth member of his Organization. This attempt, too, failed thanks to Lea, Donald, and Goofy.

As the Thirteen Darknesses return back to their timelines while short one member, Xehanort tells his opponents that the battle between his Darknesses against their Lights will happen and they will meet again at the fated place. Because of this threat, fearing Xehanort would go after the Princesses of Heart if they did not go through with it, Yen Sid and Mickey resolved to gather the Seven Lights. After Riku awakens Sora and Yen Sid grants Riku the title of Master, it is revealed that Lea can also wield the Keyblade, making him another potential member. The secret ending of Dream Drop Distance reveals that Yen Sid had Kairi brought before him to teach her to wield her Keyblade, likely making her the seventh Light.

Members
1. Sora - A boy from Destiny Islands. His heart became connected with Ventus' before he was born and five years later it became a refuge for his heart as healed after his battle with Vanitas. He wields the Kingdom Key, a weapon originally intended for his friend Riku but it chose him after Riku fell to the darkness. His heart later became a refuge for two more hearts, his nobody Roxas and his replica Xion. He has been fighting the Darkness for almost a year, ever since Ansem, Seeker of Darkness attacked his home. He has been a thorn in Xehanort's side, destroying both his Heartless and Nobody, Ansem and Xemnas, which resulted in him almost becoming one of his vessels in an attempt to increase Xehanort's chance of winning. But this ultimately failed.

2. Riku - A boy from Destiny Islands who was bequeathed the power of the Keyblade by Terra. His heart fell to darkness before he could get his intended Keyblade and was later possessed by Ansem, Seeker of Darkness. Ever since he was on a path for redemption and as developed a resistance to darkness, resulting in Keyblade Soul Eater evolving into Way to the Dawn. He helped Sora oppose Xehanort when ever he could, including helping DiZ restore Sora's memories and protecting him in the Realm of Sleep, and later became a Keyblade Master.

3. King Mickey - The King of Disney Castle. Mickey became a Keblade Master after being trained by Yen Sid, a former Keyblade Master. He became friends with both Aqua and Ventus during Birth by Sleep and, even though he never actually met him, considered Terra a friend too because of this. He helped defeat Vanitas, Ansem, Xemnas and helped prevent Xehanort from making Sora one of his vessels. He knows where Aqua is due to him running into her during the first Kingdom Hearts but was forbade from telling anyone by Yen Sid, as he believed either Riku or Sora would try to save her without a plan for getting back out.

4. Aqua - A Keyblade Master trained in the Land of Departure. She was trained along side her friends Terra and Ventus by Master Eraqus. She was skilled in both fighting and magic and eventually was bestowed the title of Master. She later met a girl named Kairi and, in moment of protecting her, accidentally bequeathed a the power of the Keyblade to her. She later became a pawn in Xehanort's plan, resulting in her friendship being strained, but they eventually opposed Xehanort together which resulted in Terra's possession and Ventus losing his heart. She later hid Ventus in the Land of departure after it hell to Darkness, turning it into Castle Oblivion, and fought Terra-Xehanort which resulted in her being trapped in the Realm of Darkness. She was later found by Mickey and she help him get to the Keyblade of Darkness but she was dragged back into the Darkness before she could get any further.

5. Ventus - A Keyblade wielder trained in the Land of Departure. He was the former apprentice of Xehanort but he was used in an attempted to summon the X-Blade. However when he failed to summit to the darkness Xehanort extracted the darkness from Ventus' heart and made an artificial being of pure darkness, naming it Vanitas. Xehanort planned to leave Ventus to die on Destiny Islands but he survived thanks to the help of a new heart that fixed the broken parts of his heart, essentially making him an artificial being of pure light like the Princesses of Heart. Xehanort, seeing potential in Ventus, left him with Eraqus to be trained. But Eraqus knew that Xehanort was planning something and sought to make sure that Ventus never left the Land of Departure. Five years later Xehanort enacted his plan which involved Ventus fighting and fusing with Vanitas to for the X-Blade, but Ventus destroyed his heart to prevent Xehanort's plan. This resulting in his heart being drawn to and eventually resting in order to heal inside the heart that saved him, which belonged to a young boy named Sora.

6. Kairi - One of the Princesses of Heart from Radiant Garden, but currently lives on Destiny Islands with Sora and Riku. Not much of her time from Radient Garden is known, but we do know she had a very loving relationship with her grandmother. One day when she was picking flowers she was attacked by a group Keyblade of People's HeartsDestiny Islands. She became friends with both Sora and Riku and spend years playing together. But one day Ansem, Seeker of Darkness attacked the Islands and Kairi's heart ended up inside of Sora's. After a long adventure to Radiant Garden, know called Hollow Bastion, Sora used the Keyblade made of the other Princesses hearts to free Kairi's heart from his, turning himself into a Heartless. But Kairi recognised him and used her powers to turn him back to normal. After Sora's battle with Ansem the two became separated as the Worlds reformed and he decided to stay in the Realm of Darkness to save Riku. After a year Kairi nearly forgot about Sora until she came into contact with Sora's Nobody, Roxas, via her own Nobody, Naminé. This inspired her to try and find him and eventual ended up at The World That Never Was where she reunited with Riku who gave her a Keyblade to help fight of the Heartless. After defeating Xemnas and hearing of Riku and Sora's adventures in the Realm of Sleep she decided to try and help them fight. So she was placed in a World where time was of no consequence created by Merlin to train with Lea.

7. Lea - A man from Radiant Garden and the true persona of the Nobody, Axel. When he was young he was best friends with a boy named Isa even though they got on each others nerves. Whenever he met someone new he would introduce himself by stating his name and ask if they "Got it memorized?" until they become friends with him. One day he met a boy named Ventus and did his usual routine, prompting Isa to ask why he does that. He explains that he wants everyone to remember him so he'd live on in people memories, thus being "immortal". They later became an apprentice to Ansem the Wise and years later followed Terra-Xehanort after he overthrew his master. This resulted in them being turned into Nobodies as part of their research, him taking the name "Axel" and Isa becoming known as "Saïx". The two of them, and the other apprentices, followed Terra-Xehanort's Nobody, Xemnas, believing that he'd make them human again and thus they formed Organization XIII. But little did he know this meant he had become a candidate for becoming a vessel for Xehanort. One day he met a new member of the Organization, Sora's Nobody Roxas. He was ordered to be his chaperone to show him the ropes of being a member and the two became best friends. He was then tasked to eliminate traitors of the Organization at Castle Oblivion, during which he let Naminé go. When he returned he discovered that Roxas had became friends with a girl named Xion. Although he felt like he was getting replaced he soon became friends with her too. But he became aware that she was a replica of Sora made from his memories, which eventually resulted in Roxas leaving the Organisation after Xion ran away to discover who she really was. He decided to try and get Xion back in an attempt to get Roxas back but this resulted in Xion getting reprogrammed to attack Roxas, which resulted in her getting killed by Roxas, her Heart getting absorbed by Roxas and her eventually getting forgotten by everyone. He then discovered that Roxas was in a simulation designed to have him be reunited with Sora. He tried to rescue him but became enraged when he discovered that he had forgotten about him. Eventually Roxas reunited with Sora and Axel tried to have Sora turned back into a Heartless to try and get his friend back, even kidnapping Kairi to try and lure Sora to him, but when the Organization kidnapped Kairi from him he decided to help Sora get to The World That Never Was by sacrificing himself to destoy some Nobodies, stating that Sora makes him feel the same way Roxas did before disappearing. After having his Nobody destroyed and his Heartless destroyed at an unknown time Lea woke up with all the memories of being Axel, minus the ones with Xion. He decided that most of Ansem's apprentices (except Terra-Xehanort, Isa and Braig) had returned too and went to find the missing members. He eventually ran into Mickey and ended up meeting Yen Sid where he demanded to become a Keyblade wielder, having been inspired by the other Keyblade wielders he's met. Although cautious at first Yen Sid agreed and had Merlin create a world where time did not matter so Lea could train. Lea was eventually part of the rescue mission to save Sora from becoming one of Xehanort's vessels but in the process learned that his former friend Isa had become his Nobody again and they were on opposing sides. Lea then went back to the world Merlin had made to train where he was later joined by Kairi.