Since Four is my favorite, I think about him way too much. Here's part one of a list of Four prompts I've thought of! A lot are transformation or + magic or game gimmick based.
Becoming a dragon. So y'know how in ToTK, Zelda eats the magic kinda-elemental rock and turns into a dragon, right? Well... guess who also has encountered magic elemental rock crystal things and now has a connection to them... Four's turning into a dragon. Or four dragons? Five? Six if counting Shadow? Slowly, but... unlike Flora, Four has no idea what's going on. A good FSA (no LU) fanfic had a premise kind of like this.
Half Minish. Four is a smart baby, and Ezlo's magic chanting and flying symbols were pretty easy to replicate... it's just that using Minish magic as a Hylian leaves you with consequences. Between Four's second and third adventure, overusing Minish magic led to them developing longer ears, claws, paw pads on their hands, and most importantly- digitigrade legs and a Minish tail! The transformation isn't reversible, but it's stable now as well, so no more changes will occur.
Made of magic. Four has encountered and been affected by and held onto so many different types of magic. Plus with the splitting and fusing, Four is basically made entirely of magic now. Maybe even a sword spirit type deal. That means stuff like glowing weird magic blood, shattering on blunt impact, having insides being made of glass and crystal and metal (like the Four Sword), idk metallic hair or smth. But also, regeneration! He can get slashed open and have a giant gaping hole in his torso but it's fine it'll be fine. I got this idea from a LU fic that is unfortunately very short.
Not Link. Souls grow with experiences, as you grow as a person. Throughout your entire life, it grows. Even when it is split into pieces, it grows, as long as it still holds together. First, the Four Sword made ephemeral clones. Then, Link split into perfect copies, soul included. But his soul grew during the split, the copies developing personality. And when put back together, it didn't fit perfectly. And so the next time Link was split, he shattered. After the FSA manga, the colors grew enough to be people in their own right, and now fusing works more like Steven Universe fusion. Four people becoming a new one. Because. It is a new one. Link couldn't get put back together any more. And so, a new person. The one the chain knows as 'Four' who knows he is definitely not Link.
No Ganon. Okay so we all know the timeline doesn't work. So! We know demons are kinda a thing, i.e. Maladus and Majora, so. What if Four's big mastermind during FSA wasn't a version of Ganon. Like, at all. Just some random evil spirit demon guy.
Not a Hero. Four does not have: the master sword, a triforce piece, interactions with the triforce, interactions with Hylia, interactions with the golden goddesses, a Zelda with goddess-given abilities, no interactions with malice, or Ganondorf even, especially using prompt 5. So uh... what makes him a capital H Hero anyway? Spoiler - he isn't. What with refusing to touch the Master Sword, and the chain assuming things, he hasn't been found out yet. Maybe even Dink doesn't know, and assumed what with the titles and stuff - and being the (lowercase) hero of LIGHT - that he is one. I think Four would have figured it out though... or Vio would have and told the colors.
Zeffa being OP. So, Zeffa is Four's fast travel method in Minish Cap. A blue parakeet? Parrot? looking bird that picks up and carries around a nine-thirteen year old boy. Three could carry off an adult. Terrifying.
Cuckoos. Because of prompt 7, and because Four can talk to cuckoos in Minish Cap, he's not afraid of them! Well... not of the adults anyway. The babies are scary. But he's also used to dealing with Zeffa, so. At least cuckoos can't pick you up to drop you from a mile in the air. Sky sees this and instantly declares Four his successor just because.
Ocarina. The Ocarina of Wind (Four's ocarina) and the Ocarina of Time look the exact same. The OoT just has a triforce mark on it. All of the chain members who know the OoT's deal are incredibly confused and mildly concerned. Four shows Time how to summon his own Zeffa! Time shows Four how to play his magic songs. Some of them, anyway.
Walking on clouds. In Minish Cap, Four can apparently walk on clouds because he's pure hearted or something? So just give him that ability. Chain's on Skyloft, and Four just steps! off! the! side! and everyone freaks out and he just... stares at them. From the cloud he's casually standing on. Like they're overreacting. Chaos ensues.
Magic radar. In Minish Cap, Four can match a Kinstone and be able to sense the effect from anywhere in his Hyrule. Which isn't a large Hyrule, but it's still incredibly impressive! And I don't know how to explain it, because otherwise he'd have to run around his entire Hyrule just to find whatever changed. So maybe his magic senses are just that good. If he knows to focus on it, anyway. Four tilts his head, looks in a random direction: "Oh, a portal? Hm. Probably bad news. A shame." and the chain stares at him like ????
Force gems. So Force is basically both life force and magic. Force gems are concentrated stuff gained from fighting, killing things, or occasionally randomly occurring in nature I think? However, only Four and Wind (if Phantom Hourglass applies) have this. So clearly their swords are magic. They casually rip the life force/magic out of living things and the air to turn them into shiny rock/crystal things. Which then get fed into the sword. This is why the Four Sword got so absurdly powerful so fast using the LU timeline- Four was literally feeding it tons of magic. Also, sound familiar? Secret stones, guys?
If you made it this far, thanks for reading! I have many more Four prompts, so hold tight... although who knows when I'll post next, so don't hold too tight!