He'd been amused when she'd first called them 'her boys', and even more so when he realised that he had been included in that exasperatedly-affectionate term. And even though he was fourteen years older than her, was most definitely not a 'boy', and had been more than twice her age when she'd first coined the term, he'd never protested.
It had felt strangely right to be included in that group.
It could have been due to her tendency to show up at his apartment after he'd return from a mission, somehow just knowing that he'd been injured, rolling her eyes in exasperation at his long-standing aversion to visiting the hospital as she healed him, all the while halfheartedly scolding him for not taking care of himself.
It could have been due to the way she would always understand when he wanted someone to talk to, when he wanted to be alone, and when he wanted someone to simply be there beside him, as a silent yet solid presence, to ground him when he felt like he was drowning in his sorrow and bone-deep exhaustion.
It could have been due to the way she would show up at the memorial stone, kneeling next to him, reverently tracing her fingers over the kanji of the names of the village's true heroes, particularly Obito's, Rin's and his sensei's. Once, when he'd given into his curiosity and asked her why she'd do that for hours beside him, even though she didn't particularly know them, she'd smiled and replied, "Because they were there for you, sensei, when I couldn't be, and because it's thanks to them that you're here right now."
It could have been due to the way she had him wrapped around her little finger, without either of them realising it, on his part, until he'd found himself discretely flashing his sharingan to chase away the adolescent, pathetic, unworthy insects who'd dared to try to approach her at the bar, while she obliviously gestured wildly at him, slopping her sake all over herself (and him as well), in the middle of retelling an escapade of hers that he'd listened to about twenty times already that night alone, conspicuously Icha Icha-less, like it was the most natural thing for him to do.
It was then that he realised that maybe, just maybe, his feelings towards his pink-haired former student were more than platonic.
This realisation had led him to strive to greater heights, to be strong enough that he would always be able to protect her(though she'd always pouted whenever he darted in front of her, had always insisted she could take care of herself-), and to return home from every mission, no matter how impossible it seemed, to protect her heart. (Because he was certain that she would be one of the few who would shed truly heartfelt tears on his behalf.)
This realisation was also what led to him feeling like his heart was being ripped out of his chest, even as his stomach dropped and he cried her name in anguish and desperation, because he knew, he knew that he was too late, that he couldn't save her.
And he could not accept it.
Yet, even as he stumbled forward on stiff limbs paralyzed with chakra exhaustion and fear (how was he still standing?), wide mismatched eyes fixed on the scene before him, the chilling realisation that he had to accept it, because there was nothing else he could do, settled into his bones.
Seconds later, he wished he could close his eyes (but not as hard as he wished she would get out of the way, that she would be safe, that someone would save her, because he couldn't-), for his sharingan recorded every second of his precious girl being torn apart, literally and figuratively by two of her boys, searing it into his retinas and into his brain forever.
Recorded her last smile, in all its tragedy, its beauty, and its love, as she looked behind her, into his eyes for the final time.
Recorded how that gentle, devastatingly beautiful expression (her last smile, never again, her face would never light up in that happy, endearing smile he loved so much-) morphed into one of agony, as she stood between her two boys, sacrificing her life to save theirs.
Recorded her lifeless body as it fell, in achingly slow motion, only to be caught by the arms of the very people who had killed her.
Please, God, if you're out there, please, save her, I'll give anything, I'll do anything, just please, please, pleasepleasepleasesaveher, because, because....
Because she was the glue that held him together(though she'd never known just how much he'd needed her, and he regretted every minute he never told her that-).
And he'd fall to pieces without her.