Agon sees it coming when Unsui stops touching him.
Unsui's never been very tactile anyway, but he's never been hesitant before, to punch Agon lightly on the shoulder, to jump him from behind and wrap an arm over his shoulders, to ruffle his hair, to pull him along by a hand or a wrist when he's wandering too far from their parents.
Mom dies and everything changes.
They finally get their own rooms, Agon's top bunk moving to their mother's, along with his desk and chair and clothes and toys. Agon takes after their father- neither of them are sentimental- but he notices when Unsui stops spending time in his room, starts spending more time at school and taking the long way home, quietly ducking around the corner to head upstairs when he gets back instead of announcing his presence like he used to.
It's a gradual change. It's like Unsui leeched warmth from their mother and then radiated it to everyone else but now that she's gone, he's running on reserves and there isn't much left. He stops ruffling Agon's hair- dad does it all the time, still, and Unsui stops hugging Agon so much, and leaning on him and they hardly play with each other anymore.
They're in their second year of middle school when Unsui stops looking to spend time with him entirely. It's a frosty, resigned sort of distance and it drives Agon nuts because it feels like he's losing his brother, who had until then been essential and constant, like his limbs, like food and water and air.
It goes on for a month before Agon realizes that Unsui isn't doing this consciously, though he's probably aware of it- and he decides to make up for lost time through high school, when they'll actually have to live together. Unsui doesn't have any hair to ruffle so Agon starts rubbing his head instead, and using his shoulder as an armrest, and he didn't shove his twin all that much before but he starts now.
Unsui takes it but doesn't push back, keeps his hands to himself, tells Agon to stop but never takes any action, as if every time he tries to counter is another reminder of his own shortcomings whenever it doesn't work. He puts up a passive sort of resistance instead, a solid layer of ice over the speeding current Agon knows is still underneath, unflappable in the face of an oncoming storm.
After the match against Deimon, after the field's cleared and they're back in their dorm and Agon's sulking on his futon, Unsui sits down next to him and hands him the team's training schedule. In the school gym, he's the one who usually spots Agon on the bench, though they don't do much talking.
They win the Kantou Tournament the following year and Unsui squeezes his upper arm through his jersey, after their final touchdown, then goes to join the rest of the team.
Unsui keeps initiating contact but never directly, always with a cold water bottle pressed to Agon's arm or a light nudge through his shoulder pads and towels dropped unceremoniously into his lap or over his shoulders. It's a gradual thaw, but steady and unrelenting, and Agon doesn't make it any more difficult than it absolutely has to be because he isn't nice- but for his twin, he doesn't have to be cruel.
It's summer when they finally find an apartment worth staying in for the rest of their college years, and they spend the entire break week making the place livable.
"That's it," Unsui says absently as he dusts off his hands, turning back to the living room of their new place, taking in the lines of furniture, all arranged for maximum comfort and ease of use rather than aesthetics, regarding the doors to their rooms (arranged identically; for all the ways they differ, they had shared a bedroom for years and both of them know this setup best) with a mixture of apprehension and appreciation.
Unsui's rolled the sleeves of his t-shirt over his shoulders, cuffs of his fitted jeans folded halfway up his calves and he flexes his bare toes against the smooth wood floor.
Agon rakes his fingers through his hair, short braids in preparation for dreading flopping back down into his face as he exhales, long and loud, and then he sprawls out on the couch. He'd been forced to help clean- which is usually Unsui's deal, but the older twin had made it abundantly clear that Agon will be doing his share of it or else living will become an endless hell of nagging, so now he's dirty from scrubbing out the stove and he's sweaty, clothes (borrowed from Unsui because hell if he's messing up his D&G and Hugo Boss shit) rumpled. Agon closes his eyes and lets his arms droop over the side and armrest.
There's a pressure on his cheek, where Unsui's thumbing away a smear of grease or dirt or something, and then a pair of hands on his knees, pushing them lightly to make room to sit.
(Agon doesn't move his feet at all, though, so Unsui plops his ass down directly on his legs. Asshole.)