Chapter Text
Mephisto stands from his table at Vatican headquarters. “As you know the paladin awoke from his coma-
“Yes but what of the satan spawn?” A masked figure asks standing slamming his hands on the table.
“The twins know that there adopted father is awake.”
“That was not what I asked. I asked are they dead!”
“Now, now what reason would I have to kill two innocent children? They have done nothing to anyone here in fact if I remember correctly Rin saved you from Amiamon so why do you continue to chase after them?”
“They are demons the literal definition of evil,”
“Perhaps, but they were raised human, they know nothing of what being a demon truly is,”
“Yes, But what if they were exposed to Gehenna what would happen?”
“Well I suppose the older one would be forced to a full demon form and the younger one would probably be fine with little to no change,”
“That is exactly why they must be executed!” A new voice calls out. This one with a hood covering his face.
“The mental state of the boys will not be changed, they will only change appearance-wise,” Shiro says entering the meeting hall. “Didn’t Rin save this place from Amiamon so why doesn’t that clear his name?”
“Paladin, why would you of all people defend demons?” The hooded figure asks. “Where you not put in the hospital because of one?”
“Why would I defend a demon well, I recently delivered that some demons who attack people have either been a attacked first, disrespected, hurt, or they are going through the demon equivalent to puberty. And second, those two are my kids!”
“Meetings over we will meet again in a few months to discuss this further. Mephisto I want you to test what happens if the twins are exposed to Gehenna.” The masked figure instructs.
“I’ll get right on that! eins zwei drei,” He says and with a poof, he’s back at True Cross.
.....................
“Yukio, Mephisto’s comes Home today right?” Rin asks from the floor in the bedroom.
“Yes, he is. Hey, are you ok?” Yukio says turning around in his chare. To look at Rin who looks like he has a headache.
“Everything hurts, not bad or anything but, it hurts!” Rin says bouncing on his feet as he hadn’t been able to release his pent up energy for a while.
“Really, it sounds like the curse is wearing off.”
“Oh! really?” Rin says excitedly before deflating.
“What’s wrong?”
“I’m not sure. I should be happy and I am but I-I Don’t know, stuff feels right, and I don’t want to lose it,”
“Hello, baby brothers!” Mephisto yells as he enters the room.
“Last I checked there is only one baby in the room.”
“Well appearance wise I’ve seen you playing with Rin’s toys, don’t you dare deny it.” At this Yukio turns a bright red.
“Meffy!” Rin yells throwing himself at Mephisto.
Mephisto catches Rin and asks. “So what happened while I was gone?”
“Oh, it was fun! We met Bezlebub and Egyn.” Rin says clinging to Mephisto’s arm.
“The curse is starting to fade,” Yukio says having composed himself.
“That’s good,” Mephisto says suddenly serious. “You know how I had a Vatican meeting, well I’m supposed to give both of you essence of Gehenna.”
“Is that bad?” Rin asks.
“For you, maybe, but Yukio shouldn’t have a problem other than temporally sharpened fangs, ears, and nails much like how you looked with the Koma sword drawn.”
“When are you going to do this?,” Yukio asks tail flicking a bit nervously.
“Oh, three weeks or so. After Rin’s normal and functional.” At this point, rin was completely exhausted he was nearly passed out in Mephisto’s arms.
“Ok, so what now?”
“Well its almost night so Rin should sleep for the rest of the day. The first week of him growing up will be relatively simple he will sleep for much of it. It’s the second week when he’s around eight that it starts to be difficult,”
..............
“Hey, Yukio my lisp is gone!” Rin yells as he jumps on his brother's bed and on to his brother.
“It’s a Saturday go back to sleep,” Yukio grones as he’s jolted awake.
“But I can speak I don’t- OW, Don’t look so panicked I bit my tongue,”
“Rin, get off of me,” Yukio grunts out.
“Ok,”
After Yukio was awake enough to function he says “We are going to Mephisto’s to make sure that you aren’t getting hurt by this,”
...........
“So Rin, You went from a one-year-old to a three-year-old,” Ibis says, “The first week is easy but after that, it will get a little hectic,”
“What do you mean?”
“Well in human terms when you start your wonderful journey to adulthood,”
“Nope!” Rin yells and tries to run out the door only to get grabbed by the back of his shirt and dragged back by Ibis.
Mephisto comes out of nowhere. “If you hate it that much little brother I’ll put you to sleep for that part,” at this he raises his hands and pauses. “you know what I’ll just do that for the entire process,” after he says this he claps his hands, gets pink glitter from somewhere, and throws it over Rin.
“What, what did you do?” Rin asks slurring heavily.
“I made it so you would sleep until you at your proper age,” Mephisto explains as Rin drifts off.
“Why the heck would you do that!” Yukio yells his tail lashing the air.
“Shush, you,” Mephisto exclaims bopping his nose, “do you want Rin to wake up? ‘Not that he could wake up before the two weeks are up’”
“What was that?”
“Nothing” at this Mephisto teleports out of the room leaving Yukio with Rin.
............................
“So, any reasons for putting him to sleep beside less work for you?” Ibis asks Mephisto who was sitting at his desk building a card house.
Who shrugs “less work for everyone, it’s easier in the long run,”
“Meaning what exactly?”
“Well, for starters he won’t be in any ones way,”
“You did this just so he wouldn’t annoy you didn’t you,”
“Fine you caught me, I didn’t want to be so overwhelmed with him that I wouldn’t have time for anything else,”
“You are an interesting one brother, unfortunately, I have to leave now I should see you in about two weeks. Don’t mess up.”
“Who me never,” Mephisto says with false innocence. “Don’t die while you’re gone,”
...........................
Two weeks later
“Good news, Rin will wake up today! Bad news Rin will have to rebalance and practice his powers. You'll get him back in a day or so. -Mephisto,” Yukio reads aloud. “I should have expected this.”
.......
“So Rin how are you feeling?” Mephisto asks as Rin sits up rubbing his head.
“Like I got hit by a bus. Holy crap my voice!” Rin exclaims then bursts out laffing “I forgot how my voice sounded”
“Yes, yes that happens. Now, will you try to shapeshift?”
Rin nods and shifts into a cat that was a little bigger than Kuro. “What now?”
“Turn back and flote”
Rin complies turning back and hovers a few feet off the ground.
“Good, now try to walk,”
“Ow,” Rin says after standing and then falling on his butt.
Mephisto bursts out laffing nearly falling off his desk. “Oh, that was amazingly graceful. I applaud you, your highness,”
“Hu? Why did you call me that?”
“Well, you are a prince,”
“Well, you’ve never called me that before,”
“Hush you. That’s not important right now, try to walk again,”
Rin stands up slowly than before and shakily takes a few steps and starts walking around until he gains his balance,”
“Ok, you may go back to your dorm,” Mephisto says flicking his fingers towards the door,
......................
“Yukio I’m back!” Rin calls out to his brother.
“Rin, welcome home, there should be a package by the door,” Yukio says happily sitting down in the dining room.
“I see it you want me to get it for ya,” Rin says pick it up and looking inside it. “It’s a weird liquid thing?”
“Do you remember what Mephisto was as talking about before you changed back? The essence of Gehenna he said that he’ll come and test it out in a few days so you have time to Adjust,”