Lea

Lea is the original persona of Axel, and a close friend of Isa, Saïx's original persona. He appears in Kingdom Hearts Birth by Sleep as a teenager, alongside Isa, and returns as an adult in Kingdom Hearts 3D: Dream Drop Distance.

Kingdom Hearts Birth by Sleep
While Ventus is in the Radiant Garden, Lea walks by, picking up the Wooden Keyblade from the ground. He asks Ventus if it's his. When Ventus responds that it is, Lea calls him a baby for "playing" with it and proudly takes out his frisbees. The two introduce themselves, and then Lea calls for a one-on-one fight, finally prompting a smile from Ventus.

After the battle, Lea calls Isa out for not trying to make up excuses for his loss causing Ventus and Isa to laugh. He then states that they'll meet again someday, because he and Ventus are now friends. After that, Lea and Isa walk off and look up at the castle, apparently 'ready.'

Sometime after Terra-Xehanort is defeated, Lea and Isa's plan is revealed, as both were seen being thrown out of the castle by Dilan with Aeleus looking on nearby. In the next scene, Lea buys sea-salt ice cream from Scrooge McDuck and gives one to Isa as they stare up into the sky.

Between Kingdom Hearts Birth by Sleep and Kingdom Hearts 358/2 Days
At an unknown point in time, Lea's heart was consumed by darkness, turning him into a Heartless. However, his strong heart and will gave him the ability to continue on as a Nobody: Axel. Some time later, Organization XIII found his Nobody, who received the name Axel and was inducted into their ranks as Number VIII. It is known that he joined alongside Isa, and the two had a secret, unknown plan.

Kingdom Hearts 3D: Dream Drop Distance
A grown up Lea appears in the Jump Festa 2012 trailer, having been restored following the destruction of his Heartless and Axel. He appears in Ansem's study with the also-restored Ienzo and Aeleus, and he later stops Maleficent from attacking Mickey in the Disney Castle Library. Lea retains the memories of his Nobody, Axel.

Lea also appears in the Special Trailer released in February. He is shown waking up on the floor of Ansem's computer room, where he sees his reflection and notices the lack of tear marks beneath his eyes. He is later seen again, talking to Yen Sid in the Mysterious Tower.

In a February 2012 issue of Famitsu, it is hinted that Lea is searching for Braig and Isa. Nomura has hinted that Lea is a key character within the story.

After Sora and Riku's Mark of Mastery exam comes to an end, Lea reveals that he has gained the ability to wield the Keyblade as well.

Appearance
In Kingdom Hearts: Birth by Sleep, 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.

Lea carries around two red frisbees with black edges, each adorned with a Bomb design, which later influence his choice of weapons in the Organization: chakrams. He lacks Axel's purple, upside-down teardrop facial marks in the actual game, but curiously they are present in his official artwork.

In Kingdom Hearts 3D: Dream Drop Distance, Lea wears the Black coat he wore during his time as Axel, wields the same chakrams, and overall appears identical to his former Nobody, only lacking the tear-shaped markings below his eyes.

Personality
Lea is both childish and competitive, willing to disrupt Isa's schedule for his fight with Ventus. This is also evident during the ending credits when he is seen trying to escape from Dilan's grasp by flailing around his limbs, unlike Isa, who realized they couldn't escape and barely moved. He is also somewhat smug and sarcastic just as Axel was.

He wishes for everyone he ever meets to remember him, so he can live on forever through people's memories. Like his Nobody, he uses the phrase "Got it memorized?" on multiple occasions.

Trivia

 * In an issue of Famitsu PSP+PS3, Lea's name is misspelled "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.