|Appearance||Period 40: Midnight Kotatsu|
|Fate||Dragged into the Other World|
Yuna is a young girl with a thin frame, most-likely around the age of ten. She has long layered hair with several locks at both the front and back of her shoulders. Her long bangs frame her face with a quirked section at the middle that faces the right. She has big curved eyes.
Her attire is casual, composed of a hoodie worn with a shirt, shorts, and socks.
An eager and selfish girl who loves nothing more than counting her money and comparing it with friends. She enjoys spending it on frivolous things and gets envious if someone undeserving of it gets more than her. She is said to only think about herself, and she can become very childish when angered.
Arriving to her grandmothers, Yuna happily found her aunt and uncle and got her New Years money from them. She was disappointed upon realizing they only gave her 5000 yen this year in comparison to her younger cousin, Sora, who got 10,000 yen from her parents. Frustrated by this, she steals his money and runs off to hide as he gives chase, ducking beneath the kotatsu. She laments her grandfathers passing two years ago and recalls how he would always sneak her extra money, and with what little she got she won't be able to afford much. It was then she noticed the Entrance Seal stuck to the kotatsu and carelessly pulled it off.
At this point, Yuna decided to relax by reading some manga and enjoying her snacks when Sora eventually returned. She began to tease him before recalling the anime she wanted to watch at midnight when her grandmother informed her that children should go to bed early to avoid being taken to another world. There exists a legend saying that the kotatsu was made from the trees that used to be located in shrines, and as such they contain a portal to another world; however, grandpa did stick a tag on it so it might be okay.
Yuna begins to worry when she remembers the tag she ripped off earlier and decides to make it an early night- much to her fathers surprise. He remarks on how unlike her this is but she says little of it before noticing Sora is still awake. She scolds him to go to bed because he is younger than her, and soon everyone turns in for bed.
The following morning Yuna is awoken to find out Sora has gone missing. Everyone has rushed around the place and outside to try to find him, and realizing she still has the tag, Yuna begins to get anxious and claims not to know anything before heading off to fetch the tag from beneath her pillow. Worriedly, she realizes that her grandmother wasn't lying; but as she sees Sora's money envelope she begins to believe it was his own fault, because he didn't listen to her warning. Knowing she could be a target, she suggests to her mother that they leave now and let the police handle it, and because she has her money now she has no reason to stay.
To her shock, her mother suddenly slaps her and calls her out on being so selfish. As she slowly recovers, everyone expresses relief when they suddenly return with Sora, having found him locked in the pantry. He had wandered in there the prior evening and got stuck. Although everyone feels better, the distraught Yuna is further enraged and claims it was a lie, and that the legend wasn't true after all. Sora runs up to her in joy and she assumes he wants his money now, but feeling further angered she is inspired and she takes off, offering to fetch it and returns, having shoved the tag inside of it. She hands it over, claiming she was putting a seal on it to make sure it didn't get ripped open. She then returns to her place beneath the kotatsu, still holding the money.
That evening her parents come by to find her still sulking, and they take off after saying goodnight to her after realizing she isn't in the mood to talk to them. While still in a foul mood Yuna decides to turn in when she sees that they actually did go to bed, turning out the lights and laying down. She gets comfortable and is about to fall asleep, still beneath the kotatsu when she happens to notice that someone is still in it on the other side.
She assumes it's just a family member or Mikan, but realizing everyone else has gone to bed, she dives beneath it to hide while fearing the worst. However, she suddenly realizes their outfit but initially can't place it as they suddenly begin to approach her and left the thick blanket. To her horror, she sees it's her dead grandfathers spirit, saying he has found her and offers to give her New Years Money. Yuna is too frightened to move, and he grabs her, pulling her into the other world.
The following morning, Yuna's mother is shown observing the abandoned kotatsu and wonders if Yuna is still sulking there; unaware that she is now missing as Mikan lays on the left behind money.