Michi had not meant to stay in the mortal realm for this long. As a nine tailed fox, he was practically immortal, far outliving any being in the mortal realm.
However, he still frequently travelled down to the mortal realm in a human disguise so that he could find ways to stave off his boredom. While the heavenly realm was great, free of starvation, thirst, and sickness, things were simply too peaceful for him. Kitsune like him thrived in amusement and mischief!
And thus, he looked forward to his trips down into the mortal realm every decade, eager for more entertainment. Luckily, time was valued far more in the mortal realm and as a result, humans kept coming up with newer and more creative ways to spend their limited time.
Each decade he descended, he brought back new books and games. But, one year he found himself making the trip in only five years' time, having not brought enough entertainment on his trip previously.
Overconfident, Michi failed to calculate for the weather during his week long descent and found himself caught in a thunderstorm. Power diminished by the thunderstorm and caught in his human disguise with no tonic to regain his power, he met you. Falling in love with your kindness as you sheltered him, he continued to remain in the mortal realm, eventually becoming your husband.
You remained none the wiser about his true identity as he kept up his human disguise, using wards and herbs to maintain his waned power during thunderstorms.
Once he settled in, Michi began to grow more lax about thunderstorms again. Eventually, much like before, Michi fell asleep during a thunderstorm, forgetting to drink the concoction he prepared for such events.
That’s how it happened. Now, you were in bed with your husband, who had seemingly sprouted two fluffy ears and nine even fluffier tails overnight. They were warm, curled tightly around you.
Michi hummed, eyes still closed and oblivious as to what had occurred overnight. He nuzzled closer to you, sighing as he breathed you in. “Morning, darling.”