Suz wanted fic. Suz gets fic. Fic has cat ears.
One day, Genma woke up with cat ears.
He, being five at the time, went crying to his father to make it go away. His father just soothed his tears away with pats and strokes, and by the time his mother woke up, Genma had forgotten he even had strange ears and had dashed off to play, his ears fading into his hair and back to normal.
The next time Genma woke up with furry appendages, he was thirteen and it was on the battlefield with Iwa. It felt like someone was sitting on his spine, and it took him five seconds - his alertness and reaction time had thinned to the milliseconds, which showed how confused he was - to realise that his legs were sitting on his spine, his spine was furry, and it was a tail.
He would have spent more time freaking out at it, but right at that moment his jounin sensei yelled into their tents to get a move on, the Iwa-bastards were moving in, and Genma stuffed the too-furry tail down a pants leg and hopped to it. By the time they lost half a mile of territory and three squads and earned three field promotions to replace the lost ninja, Genma had not noticed his tail disappearing, and shrugged it off as a dream.
The third time it happened, Genma was nineteen. He had been having a rather pleasurable evening, lubricated with just the right amount of plum wine, wet lips and knowledgable fingers, but when they got to the bed part of the evening, his partner started yelling. Genma was just as lost as his partner, because while he could explain away the ears and the tail, and even the strange eyes with bad lighting, he couldn't quite explain the shredded sheets. Or the bloody lines he'd scored down the other's arms in a fit of arousal-induced passion.
Fortunately, said partner was Genma's superior, and could ship him off to the nearest medic without being blown off as a drunk ANBU seeing things, and while Genma's ears and tail had disappeared in the cold shock of sobriety, his claws and eyes more than warrented a closer look by the medics.
Half an hour later, Genma was ushered into a small little room that said "cell" more than "hospital", wearing nothing more than a hospital gown that replaced the sheet his superior had bundled him into.
A very polite, slim, dapper medic with no name tag sat opposite him in the the only chair in the room - Genma had the choice of wall, floor and cot, and he'd chosen to lean against the wall, because he might be a freak, but he was a ninja - and started talking.
"We were concerned, Shiranui-san, that you didn't seem to be showing any signs --"
"Who? what? Who's this we?"
"-- when most of the subjects were reported to have minimal signs at ages as young as ten --"
"Subjects?"
"-- and we would have written you off as a failure, but it turns out that you have the most changes." The man paused to smile benignly at Genma, who was gaping at him like a fish.
But in a moment, Genma thought, he was going to shred the man's face, unless he started explaining.
The man seemed ignorant, or unconcerned, to the sheer levels of homicidal rage Genma was emitting, and flipped some papers on his clipboard. "Perhaps we should be looking out for the later ages of turn then?" He looked up, smiled, and paused.
Mostly because Genma was in his face, clawed fingertips a hair's breadth from the man's adam apple.
"Explain. Everything," Genma said, voice silky soft, in what he was almost afraid was a fucking purr, "or I pull your vocal cords out and play fucking cat's cradle with 'em."
The man barely had time to react, before one entire wall - the one Genma had been leaning against - turned grey, then transparent.
"Were-cat," Sandaime said, his voice still raspily mild through unseen speakers. "That's what you are Shiranui-san. A new potential bloodline."
Genma couldn't see Sandaime's eyes clearly, even when he squinted.
"Come with me. I'll show you the others." Sandaime turned and moved out into the hallway, and Genma followed.