Yamamoto didn't mean to interrupt.
He didn't mean to do much of anything. Training with Reborn always leaves him exhausted in a pleasant, full-body ache kind of way, the sort of comfortable strain that reminds him of baseball and always leaves him hazy with the satisfaction of excessive physical exertion. When he reaches for the handle of the room he shares with Gokudera there's nothing in his thoughts at all, except maybe some vague consideration of taking a nap, or seeing if Gokudera's around as he so rarely is since they all started training. Even the idle thought of Gokudera is enough to make Yamamoto smile, enough to hold pleasure in the curve of his lips as he pushes against the handle, and then the weight of the door swings open and what he hears completely knocks aside all other considerations.
Someone's crying. There's no mistaking the sound, either the hiccuping inhales or the harsh sob of air on each exhale; Yamamoto's whole body tenses in immediate sympathy at the raw agony of the sound, at the rough edge of hurt under the pattern of breathing that says this has been going on for some time, for at least a few minutes and maybe far longer. He's blinking from the doorway, taking in the whole space of the near-empty room in a rush of concern, and then he sees silver hair hunched over folded knees at the end of the bed and all the air leaves his lungs in a rush.
"Gokudera," he says, before he can think better of the reaction, before he can decide whether he shouldn't just back out and shut the door and pretend he hasn't seen. "Are you okay?"
"Fuck," Gokudera grates without looking up, his voice as raw on the gasp of his tears as his breathing is. "Go away, Yamamoto."
Yamamoto doesn't. He steps forward instead, fast, pushing the door shut behind him before anyone else accidentally overhears what Gokudera clearly doesn't want to be observed before coming forward across the floor, padding closer while Gokudera's shoulders hunch tighter as if he's building a wall against Yamamoto's presence.
"Gokudera," Yamamoto says as gently as he can, but this gets no response other than Gokudera pressing his face closer against his knees. His arms are wrapped tight around himself, his face completely hidden by the fall of his hair and the cover of his knees and arms, but his shoulders are still shaking, his breathing is still catching into hiccuping inhales like he can't remember how to breathe right. Yamamoto's chest aches sympathy. "Hey, Gokudera."
"Baseball idiot," Gokudera says against his legs. When Yamamoto reaches out to touch his shoulder Gokudera flinches away and lifts a hand to smack Yamamoto's careful fingers back so hard they slam against the frame of the bed. "Don't touch me."
"You're crying," Yamamoto says pointlessly, and Gokudera tenses farther around himself, his shoulderblades shifting under his shirt like they're wings trying to break free from the weight of his spine. "Do you want someone to talk to?"
"No," Gokudera hisses. Yamamoto shifts to his knees, dropping to sit on the floor alongside Gokudera; he can feel his forehead creasing on concern, can feel his heart aching in his chest with each choking inhale Gokudera takes as if it's his own throat closing up on the threat of tears. "I want you to fuck off and leave me alone."
"You shouldn't cry by yourself," Yamamoto tells him, aiming for a convincing tone even though Gokudera isn't giving any sign of listening. He reaches out again, his fingers drawn forward by the need to offer comfort; this time he touches Gokudera's hair instead of his shoulder, and Gokudera hisses but doesn't flinch away. It's enough encouragement for Yamamoto to let his fingertips slide along the soft silver of the locks, to unwind the rumpled tangle crying has made of Gokudera's hair while the other boy hiccups and coughs against his knees. "I'm not going to leave you when you're upset."
"I hate you," Gokudera tells him, as viciously as can be managed by someone who is gasping the convulsive inhales of tears every second word. "I hate you so fucking much, baseball idiot."
"I know," Yamamoto soothes. "Tell me what's wrong."
"You are," Gokudera snaps, gulping for air he loses in another wracking sob. "Why are you here, you idiot, you're not supposed to be here."
"It's my room too," Yamamoto says as gently as he can while still pointing out this relatively reasonable fact. He runs his fingers through Gokudera's hair, feeling the strands fall out of knots under the careful tug of his fingers. "I didn't know you were in here."
"I don't mean the room." Gokudera lets one of his arms fall, lifting his head enough to drag his sleeve across his face; his eyes are red and swollen, his face is wet with tears. The seam at his sleeve catches his cheek and scores a line across the raw skin before Yamamoto can flinch and catch at Gokudera's wrist to pull his hand away. "I mean all of this." Yamamoto presses his palm to Gokudera's cheek to wipe at the damp as gently as he can but Gokudera still cringes from the contact, still turns away before Yamamoto can make more than a passing attempt at drying his tears. "You shouldn't have come to the future at all."
"We all needed to," Yamamoto points out, letting Gokudera scrub viciously at his face and contenting himself with trailing gentle affection through silver hair. "We need the Vongola rings to defeat the bad guys, right?"
Gokudera gives him a look so weighted with disdain that even the evidence of tears still clear all across his face isn't enough to undermine the response. "Yes," he says, and he sounds angry but he also sounds a little more like himself, which evens out to a win by Yamamoto's measure. "We're going to fight the bad guys. But you're an idiot. You were better in the future, you actually knew what you were doing." Gokudera's eyes drop out of focus, his forehead creases on a cringing moment of pain, and Yamamoto can all but taste the real cause of his upset in the air without even being told. "And you still." His words cut off, his eyes go liquid, and then he's ducking down again, pressing a palm hard against his forehead as he sucks in a choking breath against the inside of his sleeve.
"Hey," Yamamoto says, as gently as he knows how, and lets his fingers wander down Gokudera's hair to the back of his neck, to settle and press against the knots of tension that have been forming there at least since the other hid himself away in their room and probably long before, if Yamamoto knows Gokudera half as well as he thinks he does. "It's okay."
"It's not okay," Gokudera spits, and then he's turning, twisting in towards Yamamoto and reaching out to clutch a desperate handful of the other's shirt. His pull is rough, hard enough to topple Yamamoto off-balance into what would be the angle for a kiss in other circumstances, but now his eyes are heavy with pain and his mouth is trembling on emotion, and when Yamamoto reaches out it's to brace himself against the wall over Gokudera's shoulder instead of to pull the other in closer. Gokudera is scowling at him, his expression fraught with tight-wound emotion that is nearly fury, except that his eyes are liquid with unshed tears, and his cheeks are flushed with misery, and his fingers at Yamamoto's shirt are trembling like they're caught in a high wind.
"We let him die," he chokes off, and Yamamoto's breath leaves his lungs in a rush of understanding even as Gokudera's fingers tighten harder at his shirt. "We let the Tenth die. You and me, Yamamoto, we were supposed to protect him and we failed, even in the future we failed." Gokudera's forehead comes forward, his head lands hard at Yamamoto's shoulder; Yamamoto can feel the impact like an earthquake running through him, like lightning burdened with weight instead of with electricity. Gokudera takes a gasping inhale at his shoulder, choking over the damp in his throat, and when he blurts, "How are we supposed to do it now when we couldn't then?" it's shattered into a sob in his throat, accompanied by the weight of tears Yamamoto can feel soaking his t-shirt like the sudden damp of summer rain.
"We will," he says, and lets his arm fall around Gokudera's shoulders, lets the weight of his touch pull the other in closer. Gokudera's free hand clutches at his hip, his arm hooking into a desperate hold around Yamamoto's waist, and Yamamoto turns his head sideways to let his mouth skim the outline of a kiss against the tangle of Gokudera's hair. "It's okay, Gokudera, we will, I know we will."
"You can't," Gokudera hiccups into his shirt without lifting his head or easing his hold. "You can't know that, you idiot, how can you know that?" The words are harsh but there's something soft under his words, something fragile and tentative that makes the question a plea for reassurance as much as rhetorical insult.
Yamamoto turns his head closer to press his nose against Gokudera's hair. He smells like smoke, gunpowder and ash and the sulfur-bright of burnt-out matches; Yamamoto shuts his eyes for a moment as he breathes in, as his fills his lungs with the comfort of that smell to match the weight of Gokudera filling his arms.
"I know," he says into Gokudera's hair, and tightens his hold around the other's shoulders, fitting his other arm around the other boy to hold him doubly close. Gokudera's fingers tense on his shirt, his hold going desperate for a moment, but Yamamoto doesn't pull away, and Gokudera doesn't interrupt him. "We'll protect Tsuna together."
"Idiot," Gokudera hiccups, but he sounds a little more himself, and his hold on Yamamoto's shirt is easing into something closer to calm. "I don't know why I bothered asking."
Yamamoto smiles instead of responding. Gokudera isn't letting him go, and he doesn't move to pull away; he just keeps his hold around Gokudera's shoulders as the other's sobs ease and cease, as Gokudera's breathing stutters through hiccuping relief and back into the steady weight of calm. Even then Gokudera doesn't let his fist on Yamamoto's shirt go, and Yamamoto doesn't move except to lift a hand to Gokudera's hair and let his fingers slide easy through the silver locks.
Yamamoto doesn't have the how to answer Gokudera's need for details, to assuage all of Gokudera's constant fears for the future. But he has Gokudera breathing against his shoulder, and he has the taste of fireworks on his tongue, and Yamamoto knows that with Gokudera with him, he could do anything at all.