Three weeks after the rereveal of KH4, I've been thinking a lot about Xehanort as a mentor to Sora as one possibility for their relationship, and Sora's own darkness. And then I got to thinking about Toy Box in KH3's particular phrasing of light and darkness.
Darkness is tied to an unconnected heart. "The darkness of being alone is a power." And that's refuted by the implication that hearts seeking connection is something that is inherently related to light. But also: "You're so focused on the shadows that you forgot about the light that cast them."
That line is soooooo Dark Road coded. Baldr and Xehanort's shadows are directly tied to the strong lights in their lives (Hoder, Eraqus). But - and this is important - Baldr was forced into isolation for a week after dealing with a traumatic event, which only made his darkness worse.
Sora's light comes from his connection to other people, but the easiest source(s) of his darkness are also those other people: insecurities, frustration, anger, desperation. All of it is born from either comparing himself to them, or from his attempts to keep them safe. And it's isolating.
So it's interesting that the healthiest use of darkness as a legitimate and safe source of power is Riku. Riku, who hid his insecurities with a mask of strength, but now fully believes he has the strength to stand alone and fight a HORDE OF HEARTLESS... because he trusts and loves his support network.
Because he's worked through the shadows (his insecurities, doubts, complexes) cast by the light around him and from within him, and slowly learned to do so with other people who accepted him.
The darkness of being alone IS a power, but if that's ALL you have, you're walking a self-destructive road.
Even Dark Road indicates Xehanort in his old age was still stewing in doubts about himself, his path, his dreams, the child of destiny prophecy... and he shared those with no one, because the people in his life purposefully or unintentionally set him up to act in solitude.
Anti/Rage Form are also examples of this idea, I think. With Anti, it's the repurcussions of Sora being a heartless and reaching for power. Instead of connecting with his friends and integrating their abilities via the Drive, he relies entirely on his own brute strength.
And Rage Form is kinda like that, but more controlled. The keyblade form changes are inherently tied to the keychains, which are tied to the world. It's another way of borrowing your friends' strength by keeping them with you in this physical form. But Rage Form is just Sora's angry last stand.
"Darkness" created by people, in so far as it represents an excess of negative emotions, can basically be therapied into use. It just requires acknowledgement and reaching out. Paradoxically, the safest use of Solo Darkness is finding a Group Light you can be a part of that helps you feel safe.
Copium willing, Sora will acknowledge he has a darkness problem and confront it... with help (from Xehanort).
If (IF) the child of destiny prophecy applies to Sora in any capacity, he's gotta get less susceptible to darkness's negative effects, which - as Riku proved - starts with accepting his own.
