Notes: I googled "rabbits japan" so I could write this relatively believably, and it turns out that the Amami Rabbit is, luckily, native to two Japanese islands. Look them up, they're adorable.
And what do we do with animals? Rukia wondered, one day, as her tutor lectured about techniques for the gathering and purification of souls. She remembered the time she had been taken to the human realm for some practical exercise; human spiritual threads had been easy to sense and identify, and gradually her attention had wandered to the background of tiny, intertwining ribbons of animals' spirits. She had been unable to trace the spirits individually, no matter how she concentrated.
That must be was why her tutor had not raised the subject of animal spirits, she decided as she packed her things away at the end of the lecture: The spirits were too difficult to find for shinigami. Animals must then be able to find their own way to Soul Society. So her question was inconsequential, and she would be better off applying herself to what was necessary to distinguish herself in the Thirteenth Division.
The fact of being Kuchiki had not yet had the new, expectant edge worn off it. The question escaped Rukia's mind entirely as she scurried through the Kuchiki house to report for duty on time, praying furiously not to meet her honoured brother in the hallways.
Nonetheless, she had an answer a few days later.
- - -
Rukia smiled. The assignment had been little fuss; the hunter she had been sent for had walked through the wall of his hut, saying that he had bid his wife goodbye and was ready to depart. It was nice when she didn't have to chase a ghost, since it didn't happen often.
Then, as she strolled through the forest - there was a village nearby and a grandmother to attend to - she saw the rabbit. At first she thought she saw two, but then noticed that one's belly was a mess of red, and the one close beside it was translucent.
When the animal is bewildered, frozen, you don't hesitate. Long practise in the fields and alleys around Rukongai had taught her that.
"But I won't eat you!" she cooed as she cradled the animal to her chest, delighted that it was the truth. She had told many rabbits the same thing, trying to be kind, but she'd never been impractical with the others in the gang to think about.
The newly dead rabbit's eyes bulged wildly, and its heart was too fast for the beats to be counted. Rukia secured its paws as she held it, so that it could not scratch her, and indulged in burying her face in the rabbit's short black fur.
"You'll be my pet," she announced when she looked up, speaking softly so it wouldn't be startled. She looked adoringly at its rounded little ears, and the shades of dark brown and black in its fur. "It might take a while to tame you, but it won't matter! We have time. We'll install you in the garden in front of my bedroom - it's enclosed. You'll have a whole garden! Oh, and you'll need a name!"
At which point Rukia was stabbed and punched in the back, and fell to the ground.
"WHA-" Now she was hit in the back of the head, and got a mouthful of grass.
She had landed with her body curled over the rabbit, so she wouldn't crush it, but the second blow loosened her grip, and the rabbit squirmed away as if it was greased.
"No!" Rukia wailed, lurching forwards, arm outstretched. Her shinigami training made her far faster than any unpractised dead soul, even a rabbit.
She aborted the movement immediately at the sight in front of her.
Her rabbit stood behind another. And the new rabbit was not dead; it was death.
Rukia pulled back and sat up. She moved to stand slowly, and though she kept her eyes on the new rabbit, she saw the other one trembling behind it in peripheral vision. Rather than moving to run away, it pressed closer to the new rabbit, its pelt appearing positively pale next to the darkness of the new one's fur.
The new rabbit sat up on its haunches, then nibbled at its claws and managed to remove dark scraps clinging to them - Rukia's hand touched her back, and felt rips in her robe. This little rabbit had been those hard hits to her back and head, as it defended its claim.
Rukia took two steps back, slow, so it would not seem as if she was attempting an attack. "I meant no disrespect," she said, uncertain, and wondering for a brief moment why this blackest rabbit seemed familiar, of all things - but then she realised that her waffling was inexcusably rude, and bowed low.
The rabbit looked on her a moment more, as if in acknowledgement. Then it turned and leapt away over the grass, the other following it, and they vanished.
No one had ever told her of this phenomenon, and she had never read a reference to animal shinigami. Rukia felt as if the sight was a privilege that few were allowed. She smiled widely, awed, thinking of the noble animal sitting in front of her, implacable and self-assured ... and realised why it had seemed familiar.
Her mind's eye saw Kuchiki Byakuya at dinner time, sitting implacable and self-assured, black hair as glossy in the lamplight as fur in sunlight. But it was the thought of rabbits' twitchy little noses, overlaid irresistibly with the image of her honoured brother, that had Rukia biting her knuckles for the rest of the day to muffle laughter.
In contrition, she developed the design for Chappy the Bunny, and was proud that the Shinigami Women's Organisation adopted the sign for use - but completely unsurprised that they had. The nobility Chappy had inherited from the source of her inspiration was clear to all.