Chapter Text
It was on the first day of Yukio’s tail growing that it clicked with Rin that his brother was in a lot of pain and he couldn’t help besides cuddling up to him and act as a small heater. So far his tail was just a lump that was pushing its way out. Yukio is allowed to walk around the dorm but he wasn’t allowed to leave.
By the second day, it was pretty obvious what was happening the tail was around a foot long and was covered in a thin layer of down feathers. Which Mephisto said might turn into regular feathers or just have them in some spots. Yukio was still allowed to move around but now he had to have someone with him at all times. In the middle of the night he had thrown up, Iblis had gotten him cleaned up and set him back in his bed.
On the third day, the growth rate had decreased and as such, it was now a lot more painful. Nerves had started to grow in and the tail was able to twitch. Yukio wasn’t allowed to walk around as he would crash into walls tripping over his feet.
On day four it seemed to have started to affect him in more ways as tail related instincts had started to show up. If someone entered the room suddenly his tail would jerk up causing him to whimper. He was stuck laying on his stomach unable to move.
By day five the tail was around three feet long can move pretty well. Yukio was allowed to sit up and he was moved to Rin’s bed so his sheets could be changed as there were tiny feathers everywhere. Wile on the bed Rin decided to climb on top of his lap and sit there. Hugging his brother and pushing little bits of food into his mouth. Which made Mephisto calps to the floor in laughter.
Day six the tail was completely done growing. “Hey, Mephisto what did you tell the school?” Yukio asks his tail curling around Rin’s.
“The cram school was told that your demon blood was activating and would be back, and the school was told that you got the flu and would be back in a few weeks. So you have to teach cram school but you don’t have to go to school until you can control your tail,” Mephisto says not looking up from his game.
“Oh, I feel loved,” Rin says sarcastically. “Yukio gets time to adjust, but I just get tossed into school,”
“Oh hush,” Iblis says poking Rin’s side then puts him on his shoulders. “Yukio, for now, try not to get your tail wet as it will probably be overly sensitive with all the new nerves,”
“I’ll keep that in mind,” Yukio says, he has come to terms with his demon side after thinking it over and talking to Shiro who was there until he got called to go on a mission.
A few days later Yukio was able to walk without tripping over his tail so Yukio heads to the Cram school with Rin to teach his lessons.
“As Mephisto told you my demon blood awakened, now this doesn’t change anything as I wasn’t sealed so I have no problem with holy objects or other things that effect demons as I am mostly human. Moving on today’s lesson is on poisons that affect humans but can act as medicine to demons, before any questions to me they are still poison, and we haven’t tested Rin as in his current state it would be like testing an old bulletproof vest on a person” Shima’s hand drops back to the desk at this. “A good example for this poison I normally would be belladonna more commonly known as deadly nightshade,”
As the lesson drags on Rin begins to grow increasingly bored and starts to fidget in his seat, until he falls out of his chair. The entire lesson stops and everyone is staring at him. “Um, sorry?” At this, the class explodes into laughter. “What?”
“Oh man, your expression when you fell,” Shima chokes out.
“Rin, take this,” Konekomaru says handing him a feather, that had been in his bag.
Rin grumbles a thank you when Mephisto sweeps into the room and make an announcement. “Hello, exwires And Yukio. I have come to you today to inform you that my brothers have declared that they will be having a reunion here. Why, I don’t know and don’t worry nobody will get hurt,” at this he disappears taking Rin with him.
“Can anyone tell me what plant is good for burns?” Yukio asks getting the class back on track.
.............
“So, why did you take me,” Rin asks unamused sitting cross-legged in the air, eye level with Mephisto.
“Well you've been cursed for two months now and I’ve noticed that your mental state is very child-like, so I’ve assigned Kuro to watch you and keep track of you.”
“How is that gonna work? Last I checked the cram school won’t allow familiars to come.”
“Well yes, but Kuro had a more human form but after spending to much time with humans he lost that form,”
“What does that have to do with anything?”
“Well, in short, I gave Kuro his human form back”
“Really? That’s awesome!”
“Yes, yes it is. He is still at the dorms getting used to being human shaped. He asked me to explain demon forms to you. So I will, lower levels like coal tars have the one form, mid-levels have two a demon form and normally an animal-like form. As for us high levels we have several. We have the human form, what you looked like before getting cursed, a demon from which you are slowly getting and an animal form we are special though and are able to do most animals.”
“Ok, but what will happen I don’t think that he’s going to want to go to cram school,” Rin says with a pout.
“Oh, you aren’t going to cram school. Not until you're back to normal. You should start getting back to normal in a month.”