Taiju has seen Senku cry twice.
The first was at the ending of October Sky, when the rocket blasted skywards, and Taiju had glanced sideways at Senku to find him sniffling into his hands. Something about scientific pursuit and the beauty of discovery, some bullshit Taiju knew was, in fact, bullshit. Senku just liked the teacher and the fact that she was dying made him sad. But not enough to sob. Just enough to choke and sniffle, to lean into Taiju’s one-armed hug.
The second was during an experiment. Something Taiju still doesn’t understand. But it something that wasn’t working, and they had tried again and again and again to no effect. Variables had been adjusted, conditions had been changed, everything was taken into consideration. But no results. Nothing. Senku hadn’t really cried then, he mostly yelled and a couple tears happened to escape. He had been shaking with rage, he had thrashed in Taiju’s grip but didn’t pull away from the hug. He protested, but almost too pathetically, letting himself fall against Taiju in a loose embrace, shaking against his frame.
The third time Taiju ever sees Senku cry is three thousand, eight hundred and eighteen years into their friendship.
It’s for an admittedly dumb reason. Taiju’s not one to shy away from his flaws, and he’s the first to admit that he’s self-sacrificial to a fault. But it’s still not something he would fight. If he sees someone in help, he helps, even if he gets hurt in the process.
Even when a cave collapses on top of him.
Mining is dangerous and difficult. They all know this. But it’s still so horrifically terrifying when the rumbling starts and the dust falls from the ceiling and they all have this collective moment of ‘oh god fucking damn it’ before they turn tail and run for the entrance.
And Taiju follows. He sticks to the back to pick up stragglers, but he runs to the exit. And for a moment, he allows himself to relax. It’s close, everyone’s there, they got out safe.
But there’s a sharp cry and a body collapses and Taiju doesn’t even think before doubling back, scooping them up with one hand and tucking them under his arm. But he’s ducking and weaving between rocks and the rumbling is closer than ever and Taiju thinks to himself ‘shit, this doesn’t look very good’.
Taiju’s always been one to follow his gut. So he does, like always, and throws the person as far as he can, sprinting as much as he can before the cave finally gives way and the rocks crumble above him.
And there’s screaming and crying and the thundering of stone and what might just be Taiju’s own shouts of pain, but there far beyond him. For the most part, everything just kinda goes black.
And then he opens his eyes. The ceiling is animal hide, one of the crude base camp tents that they set up. Taiju’s stiff and achey, like he did a hard workout and didn’t properly stretch, and when he sits up its with a wheezy groan.
At least, he tries to sit up, before there’s a firm hand on his chest. Taiju blinks at it, before following its path, connected to an arm which is connected to a torso which belongs to a Senku. A very irritated Senku.
“You’re mildly concussed.” He says shortly. He pulls his hand away after a moment, sitting back on his haunches and sighing. “You’ve been out for a couple of hours. Luckily, none of those rocks hit that thick skull of yours, but you should still take it easy.”
Taiju doesn’t say anything. His tongue feels heavy in his mouth, but more than that there’s a bite to Senku’s words that he’s never really heard before. An edge that feels like the fangs of a wounded animal, the blade of a falling warrior. Something so viscerally defensive, like it’s designed to make you recoil.
But Taiju’s always been one to face strife head on.
Senku’s got his back turned. He’s busied himself with some chemicals or bandaids, stuff Taiju can’t quite see. Not that he cares, because all he can focus on is that venom, that edge, that bit of jaggedness to Senku’s voice that just isn’t leaving.
“Chrome and Magma and the others were able to dig you out.” Senku continues. “Even with Kohaku helping, it took just over a couple hours. Your face was so gray and there was a pool of blood, they all freaked out and thought a falling rock killed you—“ his voice gives way slightly, and he takes a shuddering breath, “but it was only the dust. The blood was from the fall.”
A couple bottles clank together noisily. “Magma carried you back.” He continues. His voice is getting louder. “He ran all the way to me. Ryusui and I were pouring over the maps and at first I was really annoyed that we were interrupted but then I saw Chrome’s face and I knew something was wrong and I ran all the way to the tent. I should’ve gone running with you, before all this shit happened. I couldn’t run fast enough, the tent seemed so far away—“
“Senku.” Taiju rasps out. It hurts to talk, his throat is dry and his mouth is filled with dust but god damn it he needs to speak anyways. “Get over here.”
And Senku barely hesitated for a moment before he stumbles over and collapses into Taiju’s arms.
It’s snotty, teary, messy. Taiju’s shirt had been removed when he was unconscious and it smears Senku’s tears all over his bare shoulder, but he barely even feels it. It’s irrelevant to the way Senku shakes and the way every inhale is like a shuddering knife pressed into an already opened wound, to the way his sobs are muffled but deafening and so so fragile.
“I can’t lose you.” Senku shakes out. “I would lose my mind Taiju, I can’t, I could never—“
“Then you won’t.” Taiju says firmly. He tightens his grip around Senku. “You won’t.”
A sob wrenches itself from Senku’s throat, and then they both abandon words entirely.