Do Keyblades Evolve with their Wielder?

[Joker'sHeartless]

Kinda long, but stay with me. I have photographic evidence.

Throughout the series we've seen characters do some impressive things with their keyblades, but something I found interesting was the idea of a character's keyblade evolving- not transforming or switching keychains, but evolving.
The difference being transformations are temporary changes in the shape and proportion of a key while maintaining the same basic parts. When switching keychains, the two keys generally have nothing in common stylistically as most keyblades are unrelated.

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This has happened with at least two characters, Terra and Aqua, and possibly also Riku and Xehanort.
For Terra and Aqua, both are shown with Earthshaker and Rainfall respectively in official promotional works and have these as their default keyblades, but somewhere between the Mark of Mastery Exams and the final meeting at the Keyblade Graveyard they canonically begin wielding Gaia Bane and Rainstorm, which are also shown in promotional works and appear in future installments with the Lingering Sentiment and Aqua's armor when she saves Terranort from the realm of darkness. Both keys are clear upgrades of the previous pair while retaining similar designs and names (Gaia Bane is also known as Ends of the Earth). No one give yo these keys, they just show up. Something happened to make these keyblades progress to a higher or more complete form.

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The evolution of Riku's weapon is a little less cut and dry due to Soul Eater's status as a regular sword. War to Dawn is Riku's keyblade that comes to him in KH2, replacing Soul Eater as his primary weapon. While it's generally accepted that WtD uses Soul Eater to manifest, it can be debated as to weather WtD is an evolution of Soul Eater directly, or just a keyblade with a striking resemblance. Sure WtD has some things Soul Eater doesn't, but the likeness is just too strong to be a coincidence. Plus, thematically the changes can be said to reflect the growth of Riku's heart from being surrounded in the darkness (a single demon wing) to becoming stronger and walking a path of both light and darkness (four wings total, two angel and two demon). Once again, the upgrade is not shown to be a keychain given to Riku by anyone.

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The evolution of Xehanort's keyblade the hardest to prove of the bunch, mostly because we know so little about him and his life prior to being an old man bent on apocalyptic world war. If you look at the two keyblades we see Xehanort using, one as a young man, and the other as the old master, there is somewhat little in common. The both have the metallic demon wings, horned head, and the demon eye, but in different places and sizes. In fact, the two keyblades have completely different color schemes and themes, YX's themed after time while MX's seems to be just about darkness. The pattern only really comes to light when you include the keyblade, No Name, which is an obtainable keychain for defeating the BbS secret boss, the Unknown. With No Name at the front, we see a three stage keyblade evolutionary line, with YX's keyblade's odd design a now obvious midpoint.

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My question to all of you is, what do you think facilitates this change? Is it caused by great personal growth or change of heart? And why don't other keyblade wielder's experience this? Did Ventus not experience the same growth ans Terra and Aqua? Has Sora not learned enough or changed because of his travels?
What do you think of this theory as a whole?

 

[Blackdrazon]

My theory is of a strengthening of heart, one that probably takes years on the route to adulthood and Mastery, which might explain why Ven and Sora never got one, simply due to their age. Alternately, Sora and Ven might not have evolved Keyblades because their hearts are divided/crowded. Sora's been lauded for his connections to others over the individual strength of his heart, so I think it's telling that his most prominent Keyblades besides the Kingdom Key, by which I mean the Oathkeeper and Oblivion, represent his best friends rather than himself. (Indeed, most of the keychains represent friends, but contrast with Roxas and Xion, whose gears created Keyblades that represent loneliness and darkness). Sora will probably get an evolved Keyblade before the end of KH3, but I'm not surprised it's taken so long, because my theories being correct, that's not really how he rolls.

In Ven's case, you could argue (from an in-world and a real world design perspective) that the reason he wasn't given an evolved Keyblade in BBS is because the X-Blade stands in for his evolved Keyblade!

 

[Gram]

It is certainly a possibility though I don't think a change or evolution would be tied to maturity or natural growth but a change of heart or as Blackdrazon said a strengthening of heart.
Meaning I'd see it as more of a possible change but not one every wielder undergoes.

As for MX and YX we actually do know the nature of their keyblades detailed here:

— I see. Young Xehanort himself is still in Destiny Islands and isn’t able to wield a Keyblade yet.

Nomura: Right. Even when he appeared as an additional boss in Kingdom Hearts Birth by Sleep Final Mix, he wasn’t using a Keyblade

— It was when the figures started appearing in the thrones.

Nomura: Indeed. Time was stopped just as Master Xehanort was materializing. So he moved his consciousness to Young Xehanort’s body. Reacting to this, King Mickey exclaimed, “That’s impossible!” Young Xehanort was holding a Keyblade that he originally wasn’t able to handle thanks to Master Xehanort’s power. Though the keychain on it is different, the Keyblade he takes out is Master Xehanort’s.

Young Xehanort is the Xehanort that has yet to gain a keyblade, the one he was using was Master Xehanorts with a different keychain.

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As for Riku I think his case best exemplifies your theory. Whether it was just a normal sword, the basis or whatever the fact remains Nomura said Soul Eater was used as an "intermediary" for the Way to Dawn and we see this because the WtD takes much of itself from the soul eater.
Of course Riku showed in DDD that he still had his Soul Eater but whether they are separate or two different forms of one evolved weapon is unknown and debated.
But the point stands that Riku's weapon did play a role in him gaining a new keyblade after losing his original, kingdom key, to Sora in KH1.

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When it comes to Terra and Aqua well...I'm afraid that is debatable because in the theater mode it always shows their default keyblades not the evolved versions.
The only time we actually see their keyblades canonically change is after they've lost them when Xehanort tosses Terra's aside (which the LS picks up) and when Aqua sacrifices hers to save Terranort.

And theater mode aside we also see Terra's default again in the scene where Terra and Ven's keyblades rush to her aide in the Dark Realm:

(skip to her wandering the dark realm)

It's Terra's default that saves her not the evolved version held by LW. This is also a canonical scene so if that leaves Terra's keyblade form to question then I would say it does Aqua's as well since both the scene of her armor in KH2FM and the LW battle which take place 10+ years later show the evolved forms which in Terra's case contradicts the ending of Final Episode.

Of course that could simply mean Aqua and Terra's keyblades can change between forms freely also.

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Basically it's just as up in the air as the rest but I dont see why keyblades couldn't evolve through a sudden moment of growth that matures/strengthens the heart.

 

[Absent]

Every wielder and Keyblade are unique, despite their interwoven destinies everyone goes through a different journey. Some tricks are basic(Opening and locking), others are default(Summoning the blade) but some are special and new(The weapons they morph into), its how and what the wielder goes through that will determine how they handle their blades.

The Blade is molded after the heart, and the blade strengthens the heart in a symbiotic relationship, which means that some techniques and tricks will be unique to some wielders.

 

[Sephiroth0812]

Of course that could simply mean Aqua and Terra's keyblades can change between forms freely also.

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Basically it's just as up in the air as the rest but I dont see why keyblades couldn't evolve through a sudden moment of growth that matures/strengthens the heart.

Or it could simply mean that Ends of the Earth and Stormfall are in fact just Keychains attached to the basic forms of Earthshaker and Rainfell.
The issue with the Keyblades saving Aqua in the RoD being their base forms definitely points to the explanations that Keyblades always retain their base forms.

Xehanort's blade doesn't count anyways since it was outright stated to be a keychain issue and Riku's case, while mysterious, isn't really an evolution of a Keyblade because Soul Eater is just a normal sword that was eventually used as a base to create a Keyblade/give the Keyblade that chose Riku a physical form.

 

[The_Echo]

The Blade is molded after the heart, and the blade strengthens the heart in a symbiotic relationship, which means that some techniques and tricks will be unique to some wielders.

Yeah, this is very well-illustrated with Birth by Sleep and Dream Drop Distance, where all playable characters have exclusive abilities.

 

[Gram]

Or it could simply mean that Ends of the Earth and Stormfall are in fact just Keychains attached to the basic forms of Earthshaker and Rainfell.
The issue with the Keyblades saving Aqua in the RoD being their base forms definitely points to the explanations that Keyblades always retain their base forms.

That's possible and honestly the keychains is what I lean towards myself too but it doesnt rule out his theory either even if simply because we know little about keyblades.

and Riku's case, while mysterious, isn't really an evolution of a Keyblade because Soul Eater is just a normal sword that was eventually used as a base to create a Keyblade/give the Keyblade that chose Riku a physical form.

Which the OP done pointed out:

The evolution of Riku's weapon is a little less cut and dry due to Soul Eater's status as a regular sword

But if they can shape themselves from ordinary objects who's to say they cant further change their shape in permanent ways?
This is what I meant when saying it best exemplifies.

Given how little we know there's actually nothing we have to confirm the possibility isnt there.