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“I do wish you didn’t live quite so far all on your own,” Izuku’s mother sighed as he adjusted the straw sandals on his feet. “Wouldn’t you consider moving into the town...?”
“The town’s too noisy, I wouldn’t be able to focus on my work,” Izuku said, his tone warm yet firm. They had discussed this before. “I like my house. And it’s not that lonely, really.”
Saying his goodbyes to his mother and promising to visit again soon, Izuku set out on the road to return home.
Izuku was a scholar, researching ancient texts and folktales. It was true that his job involved endless hours of peering over faded scrolls and deciphering complicated texts, but if he set his mind to it, he could have moved to the town like his mother wished. It would have been convenient in many ways: there were barely any people living in the vicinity of Izuku’s house, the nearest human village being a couple hours’ walk away. The path was treacherous and Izuku had no business going out in night time, when all kinds of creatures roamed the forest. And yet Izuku persisted... because there was another reason why he was so reluctant to leave his humble abode.
The sun was just about to set when Izuku made it home. He lit a fire in the sunken hearth in the middle of the room, hung his travel cape on the wall and put a lit paper lantern outside his door before starting on dinner.
It was already dark outside when he heard a rustling sound from the door. He leapt to his feet – his expected visitor had ripped the paper screens with his claws in the past when he had been unsatisfied with how long it took Izuku to open the door.
As soon as Izuku pushed the sliding door aside, something nimble and red slipped past him into the room.
“Good to see you again, Kacchan,” Izuku greeted his guest as he pushed the door closed, making sure that the spirit-repelling protections were properly in place so nothing else sneaked in during the night.
The guest – a fox with frighteningly intelligent eyes and a very long, fluffy tail – circled the room for a moment before transforming into a handsome young man. No matter how many times Izuku watched this happen, it never failed to mesmerize him. Alas, the mysterious air was soon lost as the man's beautiful features twisted in a displeased scowl.
“...Stinks.”
“Don’t complain, it’ll be fine after we take a bath,” Izuku laughed. Katsuki always complained about the stench after Izuku visited human communities. Izuku walked close to Katsuki and reached up for a kiss, allowing Katsuki to rub his clawed hands all over Izuku’s back as if he could physically brush away the unpleasant smell.
As they pulled apart, Izuku brought his own hands under Katsuki’s face, palms up. The fox-man opened his mouth and a pearly white orb dropped on Izuku’s hands. Holding it like the most precious thing in the world, Izuku put the orb on its designated place next to his home altar.
Katsuki was a kitsune, and the spherical jewel was his hoshi-no-tama – a manifestation of his soul. Seeing the jewel always filled Izuku with nostalgic fondness, for it was this very item that had brought him and Katsuki together.
As a child, Izuku had once played close to a stream at the foot of the mountain when he had found the beautifully glowing jewel in the water. He had caught it in his hands, marvelling at the otherworldly treasure, when he saw the kitsune in his human form, staring at him from a distance.
At the time, Izuku didn’t know it, but he would surely have been killed if they had met under any different circumstances – Katsuki wasn’t the type to let humans see him so easily. He had been careless: he had only turned 50 years old, at which age he had finally gained the ability to shapeshift. However, holding his hoshi-no-tama was much more difficult when not in his original form, so he had left it on the ground next to the mountain creek – not realizing that it had fallen into the water and carried downstream straight into Izuku’s hands. The jewel contained Katsuki’s magic: if he was separated from it for too long, he would die, and he couldn’t take it from Izuku by force. He had no choice but to ask for his treasure back and hope that the human wouldn’t demand a steep price in exchange.
To his great amazement, Izuku had offered the jewel to Katsuki freely, giving him a sweet smile and saying he was glad Katsuki hadn’t lost something so important to him. That had been the beginning of everything.
After taking a bath and eating, Katsuki and Izuku lay down on the futon and enjoyed each other’s company and the warmth of the hearth. Izuku rambled quietly about his travels while Katsuki mostly settled for occasional comments. His tail swished back and forth in a relaxed manner.
The tail was not the only sign of Katsuki’s true nature. In the dim light of the house, his figure seemed slightly luminous and the shadow cast on the wall was decidedly that of a fox. His face was a bit too long and narrow to not cause suspicion, let alone his blonde hair and crimson eyes. Izuku didn’t really have the heart to tell Katsuki that his shapeshifting still left quite a bit to be desired, even after years of practice. Once, he had made the mistake of asking Katsuki (purely out of scholarly interest!) why he chose to take the appearance of a young man when most of his kind opted for the form of an attractive young woman. The prideful kitsune had taken the question to mean that Izuku would have preferred him as a pretty girl – it had taken Izuku a good while to appease Katsuki enough to salvage their relationship.
It still blew Izuku’s mind that he had anything at all with Katsuki. It was meeting the kitsune that had inspired Izuku to become a scholar, to learn anything and everything he could about him and the other wonderful spirits and creatures that humans knew only from snippets of old stories.
He genuinely had no idea what had compelled Katsuki to stay with him, becoming his mischievous yet oddly faithful companion and (much more recently) his lover. Was it curiosity, just a way to pass some time? What was a couple decades to a being that could live for a thousand years? If Katsuki was after his life energy, as some of the ancient stories suggested, would he leave once Izuku became old and tired, unable to satisfy him?
Despite occasional anxiousness, Izuku couldn’t bring himself to worry about the future so much when Katsuki was with him. The way Katsuki never failed to come to his door when the paper lantern was lit, how tenderly he stroked Izuku’s scalp with his clawed fingers and lied with him until morning, when Izuku began his work and Katsuki disappeared into the forest in his fox form.
“You’ll be seventy soon,” Izuku murmured. “Only thirty more years until you grow your second tail.”
Izuku really, really hoped that he would stay healthy and live long enough to see it.
“I keep telling you, it’s going to happen before you know it,” Katsuki insisted. “I’m going to be the youngest nine-tailed kitsune in history.”
Katsuki always said that. Usually kitsune gained a new tail for each century they lived, but Katsuki insisted that was just a pace everyone was settling for because it was average. The number of tails was tied to skill and magical ability, after all – not actual age.
“I don’t doubt it.” Izuku laughed as he said it, but he really meant it. Even if Katsuki was the only kitsune he had seen in real life, he had no trouble believing him to be a cut above the rest.
Katsuki, however, wasn’t happy with Izuku’s answer. He propped himself up on his elbow so that he was looking at Izuku from above.
“I’m going to prove it to you. When I get my ninth tail, I’ll seek you out...no matter where you are or what form you have.”
Izuku could only stare as the weight of Katsuki’s words sank in. This was new. This wasn’t just a way to kill some time or even a spiteful claim to prove a point (despite how Katsuki chose to phrase it). This was a promise, one that would extend...what, more than a dozen human lifetimes from now? Izuku could barely imagine a future that distant. Yet he also knew that Katsuki wouldn’t make such a promise lightly – just like he knew the significance of the way Katsuki surrendered his hoshi-no-tama to Izuku every night, trusting him to give it back in the morning without making demands.
Izuku came back to reality with a jolt, realizing that Katsuki was still looking at him, waiting for his answer. He smiled softly and pulled Katsuki down to his embrace, whispering into his ear,
“Don’t keep me waiting for too long.”