lil doodle for y'all... I write scripts for animatics I will!!! one day create, and many are Four centered.
Anyway, here is Four prompts part two!
Where's Vaati? So the deal with the Four Sword is that it is used to seal away Vaati. Drawing the sword means Vaati is released again. So... if Four is, in fact, using THE Four Sword - indicated by the splitting - then is Vaati just. Running around Four's era now? Options are: Vaati's free, Vaati is still in the sword somehow, Four made a functional replica??? Just, casually?, OR my personal favorite: Four totally murdered Vaati. Well, Vio murdered Vaati. He got very... uh, upset after Shadow's sacrifice... annnnd honestly Four was just. so done. With Vaati. The other colors may have made a halfhearted attempt to stop Vio. Blue definitely cheered.
Merging took time. Since Four has the Four Sword, he can merge and split whenever. But why make it easy for him? What if, after his third adventure, the colors were so different it was hard to become one? What if they tried to merge again... and it just didn't work? Cue panic. Cue arguing. They had to learn how to cohabitate, they had to learn how to trust one another - and themselves, now that becoming Link again may not be possible. Depends on you if you want them going through LU as Four or not, because it turns out - to merge again, they have to be united. Like Steven Universe fusion, the moment all four had the same goal and wish and wanted to achieve that wish together, or the moment they all understood each other - they finally merged.
Dark world time dilation. A fun premise I found used in a VERY good FSA fic (might've been pre-LU but I can't remember) is that more time passes in the dark world than in the light one! So Vio may be older than the other colors because of time spent with Shadow, as well as having known Shadow for longer than he'd be able to otherwise.
Dark/shadow magic? Based on prompt 3, Vio has more time in the dark world to do things... like learn magic from Shadow. When Four finally merged again, he had a moment where he simply... took stock of this... new ability... and promptly split apart again to let all the colors take this in (freak out some) separately. And well, Four is a curious person who likes learning things, so he absolutely kept studying it. While trying to make excuses to himself. Dot laughs at him.
Four is cat coded. And he knows it! And really really wishes he weren't!!! Four likes two (2) cats, Tongs (I do not remember who came up with Four's cat but I love them) and Shadow. All others... no thank you. He is very curious, often deadpan or inscrutable, very assessing and calculating (sometimes), prefers staying in the background and not getting involved but occasionally causes trouble from the shadows, he startles like a cat, is something of a loner and wanders between people like a cat, definitely has that quintessential smug cat look, is good at manipulating people, prefers to do his own thing and refuses to stop doing whatever he wants to do, is surprisingly powerful for his size and takes on things many times his size and wins... he's a cat. (He's also a cat surrounded by dogs... poor Four) Just think of some sort of cat meme, video, or behavior. Imagine Four instead. Have the rest of the chain (probably Twilight or Sky bc cats and remlits) realize Four is a cat, realize why Four is such a loner or the fact that he is one, and start to attempt to gain his trust like one would a cat's. Also if Sky makes the remlit connection he wonders if Four ever goes "night mode" lol. It ends with Four still acting like a cat... just a cat that likes you, i.e. draping himself all over the chain and flopping around like he's a liquid.
Multiplying Links. This one is simply a realization I wish for you to have. Four goes from one Link, to four Links, to five Links, to nine-to-twelve-ish-maybe-more Links. If he ever goes on a fifth journey there has to be at least one more Link than there was in LU. Thems the rules.
Stir crazy. Four is a very active person with at least one physically intensive job. He's a blacksmith, but he may be a knight as well, and we know the colors are going to be sparring on the regular. He's used to way more activity on a daily basis than this horrible endless walking! Even if it is physically exhausting as well, it's in a different, much less satisfying way. He is slowly going stir crazy, he wants to move and fight and make things! Four is also suffering from going mentally stir crazy as well. He's an artisan too, who makes things, consumes a lot of knowledge, probably helps out Dot sometimes. He needs mental stimulation! He is a blacksmith with no forge who is encountering potential new techniques and tricks and styles on the regular with this era-hopping thing, and yet he can't! study! ANY OF THEM!!!. It's like a painter cut off from any paints or canvas and then dumped into a gallery full of inspiration. Someone get Four to a forge before he explodes.
Dark magic marks. If Four a) is a dark/shadow mage, b) brought Shadow back, or c) had magical repercussions from being in the dark world or the dark mirror or a curse from Vaati or something, what if that had physical consequences? Anything from developing sharper teeth, to catlike pupils, to claws, to marks like Twilight's on his skin or black runic marks covering his hands to his forearms. If you go the "brought Shadow back" route Four could have pulled him from the mirror leaving his hands changed. This could be an angst bond with ToTK Wild who finds the others being overly conscious of his new arm... only for Four to whip his gloves off and reveal black marked arms and hands with claws that are clearly the consequences of interacting with dark magic, and then take Wild's new arm with them and smile.
Hundred year Minish portal. So, the canon for the Minish Cap is that is the game took a single day, because the portal to the minish realm opens once every hundred years for a day. For realism, let's say it's open for about however long Four's first adventure took (because it was probably longer than a day), or once Ezlo got back to normal he could portal himself back. Either way, the important thing is the portal opens once every hundred years inside Hyrule castle, and the group is time traveling. Four carefully tracks the time (as much as possible, anyway) and perhaps visits with the other realm Minish when the portal is open? They can travel to Sky's or an intermediate time and meet a young Ezlo (and Vaati?) depending on what you think Minish lifespans are.
Acrobatic Four. Minish Cap Link is probably one of the most acrobatic Links. He's also quite athletic- he has a very fast and ground covering dash roll, and climbs up and down cliffs with a grip ring. Not a ring that makes you physically capable of climbing- one that simply lets you hold on to the cliffside. (Wild is so incredibly jealous if he ever learns of its existence.) But his acrobatics are another level. From the very beginning of the game, he wakes up, stands up on his bed, and immediately does a double flip to the ground. All of his 'jumping off ledges' animations is that same double flip. He can do a double flip from a standing position, perfectly into an open vase. What the heck even is he. His jump height is at least higher than his own height to get into the vases, with the roc's cape it is between double and triple his own height. Also, with the use of Pacci's cane on holes in the ground, Minish Cap Link does about number of somersaults in place, then after those is catapulted into the air to perfectly land on whatever height ledge. He is incredibly energetic and acrobatic even upon waking up. Imagine Four forgetting where he is and just flipping out of bed.
Insomnia. Although it'd be pretty hard to be that energetic if he's so tired... which he might be. After all, Four has never had an adventure alone. And he may not have had to sleep alone in a while either. Before his first adventure, there was his dad to crawl into bed with, or sleepovers with Dot. During MC, he tucks hat Ezlo into bed beside him. The colors might pile on top of each other to sleep all tangled up, and even after becoming Four, what if he splits to sleep? Or, if Shadow is back, the two of them might share a bed, platonically or otherwise. Plus Tongs and Zeffa might hang out there too. Four is used to having an echoed heartbeat surrounding him(them), a bird trying to nest in his hair and a giant fluffy cat hogging the bed. He's not used to sleeping alone anymore. So, separate from his family, he can't sleep. And with everything going on to worry about and analyze and plan for his mind is racing. He likes taking first or second watch because he's going to be up anyway. Maybe he's one of the lucky types that don't really get eyebags, so the others don't know he sleeps so badly. At some point though, Four is leaned up against someone and just passes out.
Friendly monsters. I've seen only one LU fic in which the chain interacts with the friendly monsters in Hyrule's era. I would like to point out that friendly monsters also exist in Four's time! Although mostly there are friendly ghosts (oh yeah. Four can also see ghosts - I think he interacts with six ghosts in MC. I guess that's where Wind got it from? Maybe?) there is also a friendly Moblin. She basically takes over this guy's house, but accidentally because she turned the lights off and he was scared, I think. I also think they end up cohabitating? and she's essentially a harmless grandma despite being a Moblin. Vio also sort of hangs out with hinoxes in the FSA manga, although I wouldn't call them harmless. Either way, Four knows monsters (and shadows) can be communicated with, and even be nice!