Lounging on the beach, you sighed. Chuck had surprised you with a date to the beach. It was perfect, because just the week before you purchased a new bikini. It was a chevron pattern of gray, aqua, and a touch of black. You thought it screamed you the second you saw it at Target.
You rolled over onto your stomach, letting the sun warm your back. “I could get your back if you’d like.” Glancing up, you leaned on your elbow. “I’m sure I could get you even hotter.” Above you stood a man who looked to be about six foot five, dark hair, and a decent set of abs. His hands were on his hips, where his swim trunks were hanging dangerously low.
I’ve seen some posts joke about the fact that in KH1 it seems like Sora is the chosen one, one boy in all the world, he alone will stand against the Heartless the Nobodies and the forces of darkness. He is the slayer Key Blade Weilder but since KH two it’s seems liked everyone has a Keyblade.
The thing is being a keyblade weilder is a lot less Buffy and a lot more Star Wars
(they even have Luke Skywalker - also Terra is basically Anakin)
Keyblade Wielders are a knightly order of Master’s and apprentices. Each wielder can pass on the calling to another by allowing them to take the keyblade.
So why can so many people use the keyblade?
Eraqus, Yinsid and Xehanort are all Keyblade Masters and they all passed on the Keyblade to apprentices.
Mickey Mouse was Yinsid’s apprentice.
Birth By Sleep follows the story of three apprentice Keyblade Wielders Terra, Aqua, and Venus.
Terra and Aqua were Master Eraqus’s apprentices. Eraqus most likely passed on the mantle of keyblade wilder to them when he chose them to train. Ventus, on the other hand, was taken by Master Xehanort as a child, given the keyblade, and subjected to cruel experimentations that eventually left him with no memories. In this traumatized state he was left in Eraqus’s care.
Terra intentionally chooses Riku as his successor:
Ventus and Aqua also appoint a successor, though unintentionally.
Aqua only meant to put a spell of protection on Kairi, but Kairi reached out and touched Aqua’s keyblade.
“In your hand, take this Key. So long as you have the makings, then through this simple act of taking, its wielder you shall one day be. And you will find me, friend—no ocean will contain you then. No more borders around, or below, or above, so long as you champion the ones you love.“
Even the wooden practice keyblade is imbued with enough magic to mark Lea as a future wielder - tying Lea’s destiny to the Keyblade and to Ventus.
(Lea’s Nobody and the being formed from Ventus’s Heart share an immediate connection)
Therefor, the original successors to Terra, Aqua and Ventus are Riku, Aqua, and Lea.
In fact, Sora is the only keyblade wielder one who’s not the chosen one.
Sora is special. His heart is so full of light and love that he will literally open his Heart to others and share his Heart with those in need.
When Master Xehanort’s Dark experiments shattered Ventus’s soul - splitting his heart into Dark and Light - the pieces took refuge in the light of Sora’s Heart. The light gave Ventus the strength to return to his body and function despite only having half is his heart. When the creature Vanitas, a boy formed from the dark half of Ventus’s Heart, eventually gained human form he took Sora’s face due to that connection.
After defeating Vanitas, Ventus’s heart was re-completed and both-halves merged into one person again. However, the force of the fusion knocked Ventus’s heart from his body. So Ventus’s Heart once more took refuge inside Sora, sleeping in Sora’s Heart while his body slept in Castle Oblivion.
Because Sora had the Heart of the Keyblade wielder inside of him (literally - we’re talking about a whole separate heart here) the keyblade chose Sora. Once Sora took the Keyblade in his hands he became its wielder.
After the events of KH1, Sora opened his heart to free Kairi’s Heart, which, similarly to Ventus, had left her body and taken refuge there. Ventus’s Heart was also set free, and took human formed based on his last physical human appearance, although he did not remember his life as his memories lay within his sleeping body.
Organization XIII assumed that this creature, formed when Sora lost his Heart, was Sora’s Nobody so they named him Roxas (despite the fact he looks nothing like Sora and doesn’t remember Sora’s life - which is kind of big since most Nobody’s form themselves based on the memories of their human life. But no one questioned that Roxas wasn’t one of them, but to be fair Roxas was the only creature of his kind, a heart given form).
Obviously, since Roxas is Ventus’s Heart, he can wield the keyblade.
Xion is a replica formed from Sora’s memories. At first it only appears that she can wield what appears to be a keyblade but is in fact a replica. (whch is wy Riku call it a sham). She gains the ability to wield a real Keyblade after Roxas gives her his to use (now that she’s touched it she may be chosen).
(Art by Jadenyugi9)
Why Couldn’t Roxas and Xion exist on their own?
Unfortunately, due to how Xion was made, she is draining power from Roxas (and pulling memories from Sora). The Organization meant for her to absorb Roxas into to create a copy of Sora. Xion chooses instead to force Roxas to absorb her.
After that Roxas has Sora’s memories trapped inside him, and Sora cannot be wake unless those memories are returned to him. So Roxas goes to Sora, believing that he is Sora’s Nobody and that he is not meant to exist, only to be swallowed up by his Other.
When they meet again in DDD, Sora tells Roxas’s he’s wrong.
However, Sora didn’t know who or what Roxas truly is because he still didn’t know about Ventus being inside him.
So to Recap:
Aqua: Passed keyblade on to Kairi
Terra: Passed keyblade to Riku
Ventus: Passed keyblade to Lea, and later to Xion while he was in the form of Roxas