Lea

Lea is more often referred to as Axel due his more prominent time as a Nobody. In Kingdom Hearts Birth by Sleep, he appears as a teenager and a close friend of Isa. He appears as an adult in Kingdom Hearts 3D: Dream Drop Distance, in which he chooses to become a Keyblade wielder under Master Yen Sid.

Kingdom Hearts Birth by Sleep
Lea lives an idyllic life alongside his best friend Isa on the world of Radiant Garden, and conspires with Isa to break into Ansem the Wise's castle for the sake of mischief. The pair walks past the town square shortly after Terra and Aqua have left Radiant Garden, where Lea notices Ventus drop his Wooden Keyblade and hands it back to him, as Isa impatiently watches. Lea teases Ventus for using a "kid" weapon, and proudly shows off his frisbees while challenging Ventus to a sparring match. Ventus readily accepts, to Isa's amusement, and easily defeats Lea. Though Lea tries to claim the match is a draw, Isa chides him and the three leave to part ways, laughing. Lea vows to Ventus that they will meet again, as they are now friends, a comfort that prompts Ventus to decide to keep making friends. As they walk away, Isa asks Lea why he keeps befriending strangers, and Lea answers that he wants to live forever in the memories of everyone he meets. As they near the castle, the pair look up to it and Lea checks if Isa is ready to begin.

Sometime after Terra-Xehanort is defeated and taken in by Ansem, Dilan throws a struggling Lea and a resigned Isa out of the castle as Aeleus looks on. Afterward, the pair go to the Castle Town to buy sea-salt ice cream from Scrooge McDuck, and they look up to the sky as they eat. From thereon, sea-salt becomes Lea's favorite ice cream flavor.

Between Kingdom Hearts Birth by Sleep and Kingdom Hearts 358/2 Days
One day, Lea and Isa successfully snuck into the castle in order to investigate the mysterious cries coming from within. They found their way into the Heartless Manufactory and down into the Chamber of Repose, where they encountered a young girl known only as "Subject X". They befriended the girl and made plans to help her escape, but found that she had been moved elsewhere. In order to locate her, they decided to become apprentices to Ansem the Wise.

However, the very next day was the day that Terra-Xehanort turned on the other apprentices, transforming them into Nobodies in the Heartless Manufactory. Their strong hearts and wills allowed their bodies and souls to continue on as Nobodies. Organization XIII recruited the pair, naming them "Axel" and "Saïx" and inducting them in as Numbers VIII and VII, respectively. However, the two joined the Organization with the intention of taking it over in order to find their missing friend.

At some point during Sora's journey, he destroys Lea's Heartless.

Kingdom Hearts Re:coded
Sometime after Axel sacrifices himself to give Sora safe passage to The World That Never Was, Lea is recompleted as a human in Ansem's lab alongside Isa and the other former apprentices of Ansem the Wise. While they're unconscious, Young Xehanort appears, and he and Braig discuss moving forward with Master Xehanort's plans to create a real Organization XIII.

Kingdom Hearts 3D: Dream Drop Distance
Lea has a dream of Roxas reminding Axel of the promise he made to him and Xion, to always be there to bring them back, and he awakens, with his memories of his time as Axel intact. Discovering that four of the founding members of Organization XIII, Aeleus, Even, Dilan and Ienzo, have been recompleted as well, Lea notices that Braig and Isa are missing and decides to look for them. After talking with Aeleus in Ansem the Wise's study, he finds out there is no one else in the Castle. Deciding to check the castle grounds, Lea is told by Aeleus not to bother. Ienzo explains to Lea if Braig and Isa were recompleted, they would have appeared in the same place as the others. This makes Lea wonder if Braig and Isa could have been "blasted off to some other world", which Ienzo explains is possible if the world they came from no longer exists when they are reborn; they'd reappear in Traverse Town or a similar place if that was the case. Lea then finds the remnants of Ansem's notes about the Door to Darkness, and leaves to bring back Braig and Isa, without telling Ienzo and Aeleus how, complaining that he always gets stuck with the icky jobs.

Lea uses a Corridor of Darkness to travel to Disney Castle, hoping King Mickey would help him in his search. From inside the Corridor, he disrupts the hostage situation taking place in the library, blocking Maleficent's attack against Mickey, Donald, and Goofy and distracting Pete long enough for Queen Minnie to escape his clutches. Once Maleficent and Pete are gone, Lea reveals and introduces himself to Mickey and his friends. Revealing his motives, Lea asks for their help in his search. Lea travels to the Mysterious Tower with Mickey, Donald, and Goofy, being brought up to speed regarding Sora and Riku's Mark of Mastery exam and Xehanort's inevitable return. Seeing they need more help, Lea requests that Yen Sid make him a Keyblade wielder, shocking everyone present. Yen Sid warns him that the road he has chosen will not be easy, but Lea decides to "jump right in" anyway. He is then helped with his training by Merlin, along with Flora, Fauna, and Merryweather, by using their magic to compress the time his training would take.

Learning of the danger everyone else is in, Lea arrives in The World That Never Was, just in time to save Sora from becoming Master Xehanort's final vessel in the new Organization XIII. His appearance shocks Xemnas and Xigbar, the latter of whom calls him "Axel". Lea explains that when he was Axel, he promised Roxas he would always be there to bring back his friends and intends to make good on it, then jokes to Master Xehanort that he had plotted his "script" so well, but forgot to "write the sequel". Lea is attacked by a hooded member wielding the Lunatic. After deflecting the attack, the member's hood blows back to reveal Saïx, leaving Lea shocked to see his former friend as one of Master Xehanort's vessels. Regrouping with Mickey and Riku, Lea gives up on correcting people about his name and says they should escape while they have the chance. After Donald and Goofy arrive and defeat the Dark Figure, the new Organization begins disappearing, its members returning to their proper place in time. As they leave, Lea shares a final look with Saïx.

Back in the Mysterious Tower, Riku decides to go back into Sora's dream to awaken him. Lea tells Riku if the darkness gets him again, then he will be there to get him out, joking that "Dark Rescue" is his middle name. After Riku succeeds in awakening Sora, Lea then joins him and the others in a tea party while Riku is recovering. Once Riku wakes up and Yen Sid declares him a Keyblade Master, Lea tells Riku that he'll catch up to him in no time and become a Keyblade Master as well. Despite Sora and Riku's disbelief, he explains that he came to the Mysterious Tower to learn how to wield a Keyblade and even planned to be using one when he showed up to save Sora and Riku but hasn't been able to summon it yet. Wondering if the problem is in the way he moves his wrist, Lea tries one more time and successfully summons his Keyblade, Flame Liberator, shocking everyone present.

Afterwards, Lea soon returns to Radiant Garden to continue practicing how to use his Keyblade in preparation for the upcoming war.

Kingdom Hearts 0.2 Birth by Sleep -A fragmentary passage-
Yen Sid mentions that Lea is undergoing further training with both Merlin and the three fairies. When Kairi wonders who Lea is, Mickey explains to her that Lea was once Axel, much to her shock, but clarifies that he is now on their side.

Kingdom Hearts III
While training in the Secret Forest, Lea catches Kairi writing a letter to Sora. He presents Kairi with some sea-salt ice cream to celebrate summoning their Keyblades. Kairi gets excited to duel in the ring, telling Lea to promise not to hold back, it stirs memories of Xion. When asked to stop apologizing to her, Lea agrees on the condition she calls him "Axel". Sometime later, the pair receive new outfits from Yen Sid, but unlike Kairi, Lea decides to stick to his black coat. The pair concur that Naminé and Roxas deserve their own lives, and Lea confides in her about his old friend, Ventus, and how when he decided not to inform Roxas of the similarity out of fear that he would also vanish.

After Aqua and Ven are rescued, the Guardians of Light gather at Mysterious Tower. Lea tries to make sense of how everyone knows each other or is connected to each in some way.

Lea spends the evening at the Clock Tower, eating his own ice cream while carrying two extras for his lost friends. Saïx appears in peace and points out that Lea has taken Twilight Town as his new home. The pair reminisce on how they apprenticed to Ansem the Wise to rescue Subject X, getting pulled into the Organization. When Saïx says it's a futile effort retrieving their lost friends, Lea counters that he'll not only retrieve them but Isa as well.

The next day, Lea and the other guardians travel to the Keyblade Graveyard and fend off an immense swarm of Heartless. However, Lea gets knocked out protecting Kairi from Terra-Xehanort before a Demon Tide swallows him and the rest of the Guardians. Sora manages to retrieve Lea's heart from San Fransokyo using the power of waking, which causes a loop to occur. This time, Terra-Xehanort and the Demon Tide are fended off with help from the Lingering Will and the spirits of the Dandelions, followed by Yen Sid walling off the Heartless summoned by Dark Riku, allowing the guardians to chase after the Organization.

At the Skein of Severance, Lea and Kairi pair up to fight Saïx and Xion but are overpowered by Saïx shortly after Sora catches up to them. Xemnas appears and shatters his Keyblade, and orders Xion to kill Lea. However, Roxas's heart stirs and calls out to Xion; both their hearts return to their designated Replicas, forcing Xemnas to kidnap Kairi and flee. Lea is left to recover as Sora, Roxas, and Xion subdue Saïx. Once Saïx has been defeated, Lea expresses disgust at his friend being reduced to Xehanort's pawn. Saïx admits that he was jealous of Axel's friendship with Roxas and Xion, feeling like he had betrayed him and Subject X. Saïx promises to see Lea again, as a human; Lea watches as he fades into darkness. Lea then urges Sora to go after Kairi while he and his friends catch up.

Lea and the other guardians show up just after Master Xehanort opens up Kingdom Hearts to darkness. Lea explains that the reason he and the others took so long was due to "having some plot points needed ironing out". With his revived Keyblade, Lea joins the other guardians in holding Kingdom Hearts shut while simultaneously trapping Xehanort within his own portal.

After Sora, Donald, and Goofy defeat Xehanort within the portal, Lea and the others follow after them and share their light with Sora so that he can close Kingdom Hearts using the χ-blade. The group is then ejected back to the Keyblade Graveyard, where Sora leaves them to retrieve Kairi.

Having recovered his friends, Lea finally changes into his new clothes and celebrates at the Clock Tower alongside Roxas, Xion, Isa, Hayner, Pence, and Olette. Riku soon arrives on the Highwind to inform them that Kairi has been rescued and brings them to a celebration at Destiny Islands, where Lea plays frisbee with Isa and Ventus. They all look on as Kairi makes her last moment with Sora before the boy fades away from existence.

After one year passes by, the Twilight Town crew are revealed to studying Roxas and Xion's memories in hopes of finding the whereabouts of the missing Sora.

Design
During his youth in Radiant Garden, Lea looks about the same age as Ventus. His hair resembles his Nobody's, but shorter and with the spikes styled upward. Lea has a slight, a trait he also shares with Axel, though Lea's is more noticeable. Lea's eyes are also more of a blue-green color than Axel's striking green. He wears a sleeveless orange jacket with a white, sleeveless shirt underneath, and tan, baggy pants with red and white sneakers and black socks. The pockets of his jacket are a much darker shade of orange than the rest of it. He also wears a yellow and brown around his neck. The pattern of this keffiyeh changes abruptly near Lea's neck, from stripes to a very organized checkerboard pattern. Similar to Braig's scarf, the tip of Lea's keffiyeh is frayed slightly. He bears a curious resemblance to Hayner.

After being revived following Axel's demise, Lea wears the black coat he wore during his time as Axel and appears identical to his former Nobody, only lacking the tear-shaped markings below his eyes, and having a slightly darker skin tone.

When Riku gives Kairi and Lea their new clothes from Merlin and the Three Good Fairies, Lea opts not to wear them and continues wearing the black coat. It is after Master Xehanort is defeated that Lea dons his new outfit. He wears a long sleeveless hooded black vest, a sleeveless dark gray and red plaid button-down shirt with a short-sleeve black shirt underneath, and blackish-red pants and black mid-calf boots.

Personality
As a teenager, Lea is mischievous and childish. He conspires with Isa to sneak into Ansem the Wise's castle and flailing childishly upon being caught and thrown out by Dilan. Lea is smug and sarcastic, as shown he teases Ventus upon meeting him and exhibiting a competitive streak by challenging the latter to a duel. Lea seeks to live forever through the memories of those he meets, and he promises to always be there for his friends. Due to this, Lea often says, "Got it memorized?" as a catchphrase, emphasizing his desire to be remembered by those he meets. Lea values his friendship with Isa, who he considers his best friend. However, after turning into Nobodies, their friendship became strained, with the two friends drifting apart due Isa's personality changing too much after he became Saïx. In spite of this, Lea shows concern for Isa and sets out to find him when he notices that Isa is missing after the Organization XIII members are restored as humans in Radiant Garden. Retaining his memories from his time as Axel, Lea continues to treasure his friendship with Roxas as he considers Sora to be a friend since their respective Nobodies were best friends. As an adult, Lea acts as cocky as his Nobody counterpart. He retains his competitive streak, demonstrated when he challenges Master Xehanort while defending Sora and states that he intends to compete with Riku in the art of the Keyblade. After his restoration, Lea is often referred to as Axel by Sora and his allies, much to his exasperation, prompting him to correct them. Eventually, Lea relents to being referred to as Axel after Riku addresses him by the wrong name. Ultimately, he decides to go by Axel after seeing Kairi as Xion for a moment, believing that being called Axel was important in remembering what he'd forgotten.

Saïx notes that Lea was prone to crying when he was young; thus his Nobody gained tear-like marks under his eyes to symbolize how much Lea cares.

Lea cares very deeply for his friends, as shown in his determination to bring them back. He has a fear of his friends disappearing, after what happened to Subject X, Ventus, Roxas, and Xion. Throughout Kingdom Hearts III, Lea is very emotional about his past friendship with Isa and cries when he almost remembers Xion. His bonds with them drive Lea to fight to protect them, even if he's wounded or inadequately armed.

Abilities
As a teenager, Lea is not physically shown fighting, though he has an offscreen spar with Ventus and loses. His weapons during that time consist of two red frisbees with black edges, each adorned with a design, which later influence the chakrams Axel wields during his time in the Organization.

Upon reaching adulthood following his Nobody and Heartless's destruction, Lea wields his Nobody's Eternal Flames chakrams, and after Sora and Riku's Mark of Mastery exam comes to an end, he reveals his ability to wield a Keyblade—the Flame Liberator—that bears features from his chakrams, the Bond of Flame and Frolic Flame Keyblades, having received a magically compressed training session from Yen Sid, Merlin, and the three fairies. In Kingdom Hearts III, he fights by holding his Keyblade by its guard similarly to his chakrams, performing combos that spin it in-hand to attack, and while he is fighting Saïx, Lea shows the ability to Formchange his Keyblade into his chakrams at will in a manner similar to a dual Fire Raid attack.

Trivia

 * In an issue of Famitsu PSP+PS3, Lea's name was misromanized as "Lia". It was also once misspelled on the Kingdom Hearts Birth by Sleep official website, though it was later corrected.
 * Although it was a joke, Lea's statement that he should have been friends with Ventus rather than with Isa foreshadows future events. In the future, his Nobody would choose to become friends with Roxas rather than stay friends with Saïx, Isa's Nobody.