As a child, he loved rabbits.
There were rabbits in the moon; his mother pointed them out to him, on a crisp autumn night when the moon hung so near and bright that it seemed you could reach out a hand and take it, like a coin glimmering in the bottom of a dark barrel. He'd tried, stretching up tiny hands still sticky with sweet mochi and too much licking, and she'd laughed and caught them and swept him up to settle against her hip, and showed him how the rabbits pounded their rice, one-two, just the way his father and the other village men had done that day. Her eyes were luminous and grand as she spoke, gazing up reverently into the sky, and he did not forget.
As he grew, he wanted a rabbit to play with and keep as a pet, like the chickens that pecked and scrabbled in the yard. But chickens were useful egg-layers, and rabbits were only useful dead, as flesh and bone and soft-furred skins. His parents wouldn't waste food and care on a useless creature, and so there was no rabbit for him, at least outside of the stewpot. It was another lesson he would not forget.
Later, when that sweet, simple life perished in a thunderclap of icicles and blood, he dragged himself through the snow and envied the rabbits he'd seen skimming over the drifts like sprites, leaving neat little trails of perfect, shallow prints.
When he found him, it was winter still, snow tumbling beautiful and deadly to pile in the streets of Kirigakure; he used to search out the biggest drifts and dig nests in them, the way he'd seen stray dogs do, and curl there until morning, not quite shivering in the fragile pocket of warmth created by his own body. Those large fingers wrapped around his were the first real heat he'd felt since he'd crawled from the ruins of a shattered home, and the cold in the stranger's eyes and the warmth in his hands somehow knitted themselves to him in a link that was stronger than boiled leather or steel cable, than rot or liquor or time itself.
They spent months dodging and hovering around the outskirts, waiting for he didn't know what. While the stranger leapt between trees and made strange symbols with his hands, pausing now and then as if to listen, he remained on the ground and quietly imitated him, his dark eyes fixed upon those rough, warm fingers. Once, he heard a rush of something behind him and turned, his hands unraveling from their complicated knots, to see that the tree behind him had dumped the snow from all its knotted black branches in a cascade of melt-water, as if the sun had suddenly come out in summer strength. The stranger's eyes lingered on him at odd moments after that.
The echo of a long-past slap had rung out in his ears at the sound of the falling water. He did not try that particular twist of his fingers again.
Instead, he devoted himself to befriending the rabbit who lived under the hollow stump at which the stranger often left him. Long hours alone were spent crouched stone-still with an outstretched handful of hothouse greens. By the time they left the village, in early spring, he had only to hold open his arms and the little animal would leap into them, eager for whatever tidbit the boy had stolen this time from the glassed-in winter gardens of the mist dwellers.
Quickly and unimaginatively dubbed "Usa-chan", the rabbit was a constant companion, and for a time he was almost happy. The stranger had a name, as well. He was called Momochi, properly, but responded with only a flicker of annoyance by the time he had grown familiar enough to call him Zabuza-san. For his own part, he called him kid, or brat, or you there.
You there, stay here until I return, and don't move whatever you do.
Listen, brat, do you see this armor I'm wearing, do you see this mask? If people come wearing this armor and mask, hide there and don't let them find you. Don't tell them about me if they do.
Kid, we need to leave now. C'mon, get your things.
When they walked out of the village under the first greening leaves of spring, Usa-chan came along, cradled in skinny but loving arms.
Just outside the town limits, the furry creature seemed to realize it was being taken too far from its burrow for comfort. It twisted out of his arms and vanished into the bushes, to his utmost dismay. Zabuza-san had been following the road from the trees to one side, so that the people with masks wouldn't see him leaving. When, a moment later, he walked onto the path dangling the struggling animal by the ears, the boy's heart could have leapt out of his chest for joy.
It was not merely the rabbit. It was the first time Zabuza-san had done anything for him that was not absolutely necessary.
Still, it was not the last time Usa-chan would make a break for freedom. Over the days of traveling that followed, the rabbit wriggled free and bolted so often that Zabuza-san finally wasted money on a wire cage to carry it in. When he wanted to feed or play with it, the boy had to be on his guard from the moment he opened the little door. He became quick and efficient at catching it again, his large, dark eyes narrowed as he watched for the bunching of its muscles that preceded a leap and scurry.
Three men in masks found them, not so very long after Zabuza-san noticed his improving eyes and reflexes and began teaching him to watch for movement in the bushes and alert him when he saw it. It was he who spotted the branches moving to their left, having broken free of the hand that had pushed them carefully aside and snapped back into place with a rustle.
His tug on Zabuza-san's wrist was enough. Suddenly he found himself snatched up under one muscular arm as they flew through the air, and something seared his arm like the time he'd been hungry and tried to take the pot off the fire with his bare hands, and he cried out in fear and alarm and clutched Usa-chan's cage to his chest as the rabbit was shaken around into a panic inside.
They landed on a broad branch surrounded by leaves, and Zabuza-san clapped a large hand over his mouth and motioned him to be quiet. He nodded, wide-eyed, and Zabuza-san looked him over, then methodically ripped a length of bandage away from the swathings around his face and neck and began swiftly tying it around the place where his arm still hurt like fire. He saw the blood dripping down along his skin and nearly cried out again, as memories began boiling up inside him and froze his spine so that he couldn't move, but Zabuza-san ignored his shivering and methodically knotted off the bandage, keeping half an eye on the ground below.
One of the men appeared at the base of the tree, and Zabuza-san flinched, and through his haze of fear the boy realized that at any moment that blank mask would turn up toward them and something very bad would happen. It was then that the cage, which had been slipping slowly out of his numb fingers, fell free and clattered down and off the trunk of the tree, bouncing right off the back of the masked man's head and making him shout a dirty word and spin around trying to see what had hit him.
Miraculously, he did not look up. The cage rolled into the bushes, and the catch on the door sprang loose, and Usa-chan made her last break for freedom. The furrow she made through the brush and long grass caught the eye of the still-confused man in the mask, who shouted a warning to his partners and began flinging little knives by the dozen, every one aimed expecting a pair of humans and not a foot-long rabbit, every one missing as the terrified rodent fled. The two other men appeared from both sides, moving to cut off the animal's flight with their backs to the tree, and that was when Zabuza-san leapt down with his giant sword flashing in the sun that filtered through the waving treetops.
When it was over, Zabuza-san returned to the branch to find him crying helplessly, over the lost rabbit and the blood on his arm and all over the ground below and the fact that he was thirty feet up a tree with no way to get down. No tenderness was wasted on him, as if this man would have known how to show tenderness in the first place. He checked the bandage and made sure it was holding well, slung him over his shoulder and leapt down, and left him at the base of the tree while he walked off into the ichor-spattered bushes and rooted around in them for a moment.
He returned carrying the cage, bent in a few places but still usable, and handed it back to him.
Good job, kid. Catch another one and we'll see how it goes.
And that was how it went.