Tobirama laid on his belly on the riverbank, studying the small kanahebi lizard sunning on the rock. The small lizard's long tail suddenly swished as it raised up its eyes, alert, then scurried under the rock as shadow fell upon it.
Small quick hands grabbed the lizard before it could get away and raised it victoriously to Tobirama.
"Here," the newcomer said, trying to deposit the frantic lizard into his hands.
Tobirama gently took it from the boy and put it on the ground, watching despondently as it disappeared between the rocks covering the riverbank. He turned to scowl at the kid.
"I was studying it," he grumbled.
The boy looked up at him, then down, shoulders slumped. Five years old, Tobirama decided, and from the pale skin and the black hair, as well as its features, he could conclude the child was an Uchiha. He said nothing, for there was nothing to say. Nothing to gain from announcing his clan. The boy had chased away his study specimen, and it was only fair he would become the next one.
Oblivious to the thoughts of the other boy, Izuna grinned at him. "I can catch you another one," he said confidently. He started counting on his fingers. "I can catch you butterflies, dragonflies, cicadas, lizards, and oh, oh, I caught a blue ringed snake once," the Uchiha said enthusiastically.
"That's an Erabu Unagi," Tobirama corrected him. "A sea snake. Where did you find it?" He asked curiously.
The boy's eyes glinted, cheeks red with enthusiasm. He puffed up. "I went on a mission with my older brother and we arrived to the Islands," he said with importance. "Did you know they eat fish every day ?" He exclaimed. "I learned how to swim there."
"We went to the Islands," Tobirama corrected. "Eating fish is normal."
"I haven't had so much to eat in my entire life ," the boy said, gesturing wildly.
Tobirama turned on his heel and started going back, along the bank. The gravel crunched under his hurried footsteps, blistering hot from the sun. The boy ran next to him, jumping on bigger stones from time to time, whooping and raising a hell of a racket. Tobirama briefly considered punting him in the river to see if the boy really could swim. For the sake of scientific advancement and his peace of mind,
"I'm Izuna," the boy offered glibly. "What's your name?"
"Guess," Tobirama snapped as he stopped.
Izuna braked to a stop as well then turned to him, eyes searching. "Red eyes?" He tried with a hopeful expression.
"Scram!" Tobirama barked.
"But they're so cool!" Izuna exclaimed. "How did you get them?"
"I was born with them," Tobirama replied curtly.
Izuna's eyes widened. "You were born with the sharingan?"
Tobirama's brain screeched to a halt. "Red eyes do not mean the sharingan," he said venomously. "What, is every animal with red eyes an Uchiha?"
Izuna's expression went crestfallen. Tobirama sighed. "Certain conditions mean that some people are born with a lack of pigment in their cells, thus their hair is white and their irises lack colour, ergo, the eyes are red because they're transparent. Of you look carefully, you can see my blood veins inside," he told the boy as he bent down.
Izuna looked, fascinated. "Oooh I can really see them," he breathed.
Tobirama straightened back up. "So I am not Uchiha and I do not have the sharingan," he said flatly. "So you can go away."
Izuna looked up at him, worrying at his bottom lip. It seemed that the last line had made him suspicious, Tobirama thought.
"But if you have the sharingan you can do genjutsu," Izuna protested. "I can be under genjutsu," he said, crossing his arms. "Niisan did it to me a couple times."
Great, the runt wasn't believing him. Tobirama carefully made a note of "totally irrational" and put Izuna on his mental shelf between the lizard and the sea snake, and once more tried to be left alone.
Izuna was having none of it, following him like an imprinted duckling.
"Why don't you go play with your brother?" He snapped.
"Away on mission," Izuna replied as he skipped from rock to rock. Tobirama sighed. The Uchiha boy was oblivious to how much information he was sharing. He was like a sieve, not like the clam he was supposed to be.
"Don't step on the lizard," he warned, seeing how the boy was preparing to jump down a rock.
"Lizard," Izuna yelled as he pounced after it.
The lizard scurried away.
Tobirama beat a tactical retreat.