Author's note: This drabble takes place in the Wave Country story arc the night before Kakashi starts chakra control training with Team 7. Spoilers for Kakashi Gaiden.
A shadow crept down the hallway of Tazuna-san's modest home, pausing every so often as if to listen to the still morning. It passed several doors until stopping at one: Hatake Kakashi's. Sliding open with a smooth hiss, the door allowed the slender shadow to slip through the crack. Once inside it stilled as if trying to see the prone figure on the futon through the darkness.
Uchiha Sasuke crept over to his sensei's sleeping figure, his eyes finding the silvery tuft of hair in the faint light of approaching dawn just starting to creep through the window. He let his eyes trail down to the face, masked even in sleep, and gazed at the scarred left eyelid. Despite himself, he felt a shiver run down his spine. Was it possible?
"What do you want, Sasuke?"
Sasuke stepped back in alarm. Kakashi-sensei's body hadn't moved, his eyes were still closed, yet his voice was alert as if he'd been awake for hours. Sasuke kept silent. He heard a sigh and a moment later his sensei sat up, pushed aside the covers, and turned to face him sitting cross-legged on the futon.
"If you're going to sneak across a room, walk on the balls of your feet." Kakashi rubbed the back of his neck, his open eye looking with unconcern at Sasuke's startled expression. "I figured this was coming sooner or later, but I hardly expected to be ambushed on my sick bed."
Sasuke found his voice. "Figured what was coming?" He managed to make his voice sound as it usually did: bored with insolence underlining every word.
"You want to know where I got my sharingan."
Sasuke inhaled sharply.
"I'm not of the Uchiha clan, Sasuke," Kakashi-sensei said in a voice that was almost gentle.
"Nor am I a bastard, a third-cousin, or related to the Uchihas in any way."
Sasuke swallowed his disappointment. He knew that Kakashi couldn't have been a full Uchiha; Itachi had made sure that none of them had left the village alive, but he had hoped with a painful longing that Kakashi was in some way related. That Sasuke wasn't really the only one left.
He covered his regret with impertinence that bordered on disrespect for Kakashi's privacy.
"So, where did you get it then? Did you steal it from a dead Uchiha?"
Kakashi's right eye narrowed and, in the following silence, Sasuke wondered if he had gone too far.
"No," said the silver-haired sensei after a moment, "I did not steal the sharingan." Sea birds started to call to each other outside as the sun began to glow orange across the water and into the small room. "It was a gift from my best friend right before he died."
Sasuke didn't reply. He wanted to know more—who was this friend? If he'd been a close relative of Sasuke, he felt certain he'd have heard of this "gift." Come to think of it, how could someone even "give away" their sharingan? He was sure that the grim clan elders he remembered would never have allowed something like that. He opened his mouth, but Kakashi forestalled him.
"I think you'd better get back to bed, Sasuke. Remember, you'll need your sleep for tomorrow."
"Training, and it'll be hard. I'd hate to see you lose out to Naruto just because you didn't get as much sleep as he did."
Sasuke recognized that he was being manipulated but didn't care. He dipped his head in a brusque nod and left the room.
The door to Kakashi's room slid shut. Kakashi leaned back against his futon, feeling the pull of strained muscles. He wouldn't be very active for his team's training tomorrow. Chakra exhaustion was nothing to mess around with and even after his chakra rebuilt itself, he'd still be stiff for a few days.
Flipping over to his stomach, he balanced himself on his index fingers and began a series of pushups, testing how far his body was willing to go.
"1… 2… 3… 4… 5…"
That conversation hadn't gone as he had envisioned it. Since the day he'd met with the Third Hokage and agreed to be the jounin leader for Team Seven, he'd mentally prepared himself for the time that he'd have to use the sharingan in front of Sasuke and then deal with the questions that would inevitably follow. It was a moot point that the opportunity had presented itself much sooner than Kakashi expected. He had simply failed to give Sasuke the explanation that he wanted.
"50… 51… 52… 53… 54…"
It's none of his business, he tried to tell himself, but even if that was true, what harm did it do in telling the boy what had happened to his cousin? How Obito had saved Kakashi's life by shoving him out of the way of a falling boulder and giving up his sharingan before succumbing to his injuries… The memory was painful of course but not so painful that it couldn't be shared. After all, hadn't he faced Obito's parents and the entire Uchiha elder council?
"100… 101… 102... Ugh."
Kakashi lowered himself gingerly to the futon, resting his masked cheek against the cool cover. Only 102. Crap. He had pushed himself too far the day before and now he was definitely going to be stiff tomorrow. If Gai-kun was here he'd have a hearty chuckle at that pitiful number and then probably outdo him in pushups by 400 more.
The sun's light was steadily lightening the room, he could already hear Tsunami-san up and bustling around in the kitchen. Soon Naruto would be poking his spiky blond head out the door looking for breakfast and enquiring in a loud voice when it would be ready. And Kakashi had meant what he said about training. With a sigh he leaned over to the clothes cupboard and pulled out his vest. Digging his headband out of one of the pockets, he tied it on, lowering it over his sharingan.
Tazuna-san had retrieved a set of crutches for him, knowing implicitly that Kakashi wouldn't stick to Tsunami's prescribed bed rest. He shuffled out of his room, stiff but not in risk of imminent collapse. Tsunami-san clucked at him in a motherly way, though, Kakashi reflected with some irony, she was only a few years older than himself. No one else was in the kitchen yet, but Tsunami-san served him and left the kitchen, to wake Tazuna. Kakashi lowered his mask to eat, enjoying the peace while it lasted.
Sasuke came just as Kakashi replaced his mask, grunted in what Kakashi assumed was his version of "good morning" and sat down at the opposite end of the table, not looking at him.
Kakashi stared at the empty cup in front of him a moment, then rose, grabbed his crutches and shuffled over to Sasuke's end of the table. The black-haired boy didn't look up, so Kakashi spoke to the top of his head.
"His name was Obito. He was a cousin on your mother's side."