Rin liked being with Mephisto and Amaimon. Amaimon cared enough to sugar coat things- something like that meant a lot to Rin after a whole lifetime of people just telling him bluntly how shitty his life was or when he was doing something wrong or when he was incorrect.

With Rin's interest in courting and demon marriages came Mephisto deciding to teach Rin the proper manners for a Demon Prince, along with lessons about Gehenna's economy. He at least did it in a way that Rin could grasp the concepts he was taught, which usually entailed shenanigans by the end. Shenanigans that either led to all three of them breaking rules and ultimately being troublemakers around Campus Town or Fun Times that usually involved one or two of them against a flat surface.

On the subject of the mirror world, Gehenna had a lot to offer. The diversity of demons made it so that the culture and laws of the demon world were very accommodating to the people.

Gehenna was called the Mirror World for a reason- It didn't only mirror Earth(in its original state when it was created), but also the whole solar systems that existed in Assiah's dimension.

Different demons lived on different planets, but they had demons with teleportation abilities on each planet so they could jump through to get to other planets. Fire demons were Native to Venus, Mercury, a planet dubbed Kepler 70-b by the humans, and any fire planets(Rin would've been Native to any one of those if he was a normal demon born in Gehenna). Ghouls, Nabarius, and others like them were Native to Pluto, Poltergeist, Draugr, Phoebetor, and other undead worlds.

Earth was called Gehenna and it was where the Ruling Family always lived. Demons were much more widespread than humans would ever be and they outnumbered humans 20,000 to 1.

Rin would fit in just fine if he ever wanted to live there. Every time Mephisto told him more about the mirror world, Rin was more and more attracted to the idea of living there. It seemed so welcoming....

Currently, Mephisto was going into more detail on the subject of Fangs, Tails, and Hearts.

"Demons have three main things they grow up knowing: Baring your fangs means you're looking for a fight. If you get into an argument with another demon and one of you bares your fangs, you are challenging the other to take you down in a fight. You either have to defeat them and have them be one of your servants for however long you please, or you have to kill them." The Demon King hooked a finger around one of Rin's razor sharp fangs before letting go.

"I feel like I'm gonna have a lot of servants...." Rin muttered. He might just be one of those Demon Lords known for their temper one day....

"Having your tail out and about," Mephisto grabbed said appendage that was swaying behind Rin. The boy yelped. "Means that you're powerful enough to have it out and if anyone tries to take advantage of you showing your weakness, you'll have to kill them or just defeat them in battle to prove you are superior. It works best with an audience so no one else will try to challenge you once rumors spread." The Headmaster finished, letting go of the tail. Rin wrapped it around his waist quickly with a scowl and the demon snickered.

"Now, a demon's heart is their biggest weakness. If you can have your heart out in front of other demons, you must be the strongest amongst the demons present or you have to trust said demons very, very much, which, I must admit, never happens." Mephisto placed a hand over Rin's physical heart. He could feel it beat faster at his touch.

Rin's body temperature spiked, though he didn't show any sign of acknowledging it. His tail suddenly wanted to uncoil and wrap around the thin wrist connected to the hand on his chest. Long, slim fingers spread over his heart with long black claws. He resisted the urge and kept the wild appendage tight around his waist.

Being touch-starved was an inconvenience in this way for Rin. It got in the way of productivity involving other people sometimes. Usually, he was fine with just hugs and kisses, some cuddling. But other times, when he hadn't used his flames in a while and itched to let loose, a specific need for release burned inside him. His body would respond to any little touch and would take it out of context. The tail had been a close one, but Mephisto's warm, solid touch on his chest was too much. Well, at least he had people willing to help with said release instead of having to make an excuse, try not to seem awkward, and take care of it himself.

"Oh? It's one of those lessons, hm?" Mephisto leveled narrowed poison- green eyes on the half- demon, his signature smirk curling across his lips.

Instead of backing away with an embarrassed flush on his cheeks like the human part of him wanted to do, Rin felt a purr resound in his chest from the demon part of him that enjoyed the touch, wanting him to nuzzle into the Demon King's embrace, to make marks on his neck and collarbones and lick up the blood that would spill at the points of his fangs when he left a possessive bite on that pale, unmarked skin.

His tail squirmed in it's coil around his waist, Mephisto's eyes following the subtle movement. "Sorry, I'm just wired. Haven't had a mission in a hot minute and fire isn't exactly easy to control. Don't really have anything to do with the extra energy that builds up...." Rin muttered the last part to himself, hunching his shoulders to make himself smaller out of habit, but Mephisto had the same super hearing Rin did and smiled.

"Oh, don't apologize, Rin. I do enjoy helping you get rid of that extra energy." The Time Lord purred, leaning down to place a kiss on the teen's lips. Rin sighed in both contentedness and relief. He let himself get lost in the slow, hungry kiss. His arms wrapped around Mephisto's middle and the Demon King had one hand splayed on the small of his back, just above his tail, while the other tangled in his hair.

Rin's body went lax against Mephisto. The scent of cherry lollipops and saccharine perfume calmed him enough to not go into a frenzy chasing pleasure with Mephisto, though he knew the Time Lord wouldn't mind either scenario.

"Why don't I just treat you this time, Rin? You've got a lot on your plate and I know how difficult it is for you to maintain control over your powers all the time around these silly humans." Mephisto suggested quietly to him when they separated.

"That's unfair though...." Rin protested, unsure.

"Oh, Rin. What's unfair is you having to contain your power to such a degree that it eventually incapacitates your physical body and gives you migraines if you don't release it. And before you remind me that it's my fault you have to do that, remember that without all of these events happening, you wouldn't be nearly as successful. Trust me, Lovely, I have a plan for the future. A better one this time, too." Mephisto chided him. Rin preened at the new endearment and nuzzled Mephisto's neck. Mephisto was ridiculously tall even without his hat at 193 cm and Rin was short at only 173 cm. Rin only came to the Time Lord's neck, but that was fine, since it gave him the perfect height to attack said neck whenever he wanted.

Amaimon was only 168 cm(not counting his spike), so he was even shorter than Rin, which made the demon the perfect height to tuck himself into Rin whenever he wanted, though he was miffed that both of his lovers were taller than him.

Rin kept pulling Mephisto back down to keep kissing him. His tail uncoiled from around his waist and wrapped around the Demon King's arm, rubbing against it while they kissed slow and languid. Rin's body was getting hotter, but in a different way now.

The longer he kissed Mephisto and his tail rubbed against him in a steady rythm, the hotter Rin got until finally, Mephisto pulled the boy up so his legs would wrap around his waist and he could reach the half-demon's neck to his satisfaction.

He nibbled all over the vulnerable column of flesh and even snuck a few down to his collarbones before coming back to lick over a certain place. Rin chuckled at the action. Mephisto and Amaimon both had a thing about his neck, different from Rin'ove of leaving marks and bits all over theirs. They had certain spots they loved to bite down on and lick up the blood from after. Rin purred at the memory of the sting from sharp fangs digging into his flesh and sometimes harsh sucks to get more blood. It shouldn't have been as hot as it was to him.

Mephisto growled against that spot, like he wanted to bite it, but wouldn't for some reason. Rin whined and tilted his head back to bare his neck, to persuade the Demon King to bite him already. Mephisto instead used his own tail to flick Rin's pants open and reach in to coil around his dick, which was already hard and leaking. Rin shuddered, his head dropping back further with a gasp as the tail slowly began working him. He rocked his hips into it. His tail began to writhe against Mephisto's arm and the fur being pushed against the grain had him bucking his hips up into the touch of the other tail.

"Ngh~Please, Mephi~!" Rin pleaded. He wiggled his whole body against the Time Lord, getting more active the more they played. Mephisto growled and let his fangs just barely prick that place on Rin's neck and he moaned, anticipating the harsh sting. When it didn't come, he whined and tugged at the demon's clothes with his claws.

"Mnn, not yet Darling~You have to cum first." Mephisto breathed. Rin keened at the tail squeezing his dick a little harder now, stroking faster. "Ah~! P-Please~! Please, Mephisto~!" Rin moved against the man as much as he could, trying to get himself off.

Mephisto's hands gripping his hips stopped him. "Ah, ah! I said I'd do the work. Let me take care of you, Darling." Mephisto chided him once again. "But....I-I can't-ah~! S-so slow~! Please, faster, Mephisto~! Feels so good~! Ah~!" Rin cried in protest, nearly crying at the stalled relief.

"Please, wanna cum so bad, Mephi~!" Rin figured if he moaned the Time Lord's name more, he'd give in and go faster. The Demon King did, in fact, love hearing his name from those pretty lips and his tail constricted, gave one more stroke, before uncoiling from around his dick. Rin almost sobbed.

"Shhh, Rin. I promise this will be even better." The Demon King murmured to him. He spun and pushed Rin against the wall to keep him up against him. Mephisto bucked his hips and Rin could feel how hard he was in his pants as well. It made him shiver. "Wrap your tail around yourself, Rin." The Demon King instructed. Rin did so, shuddering deeply at the first stroke. His head dropped back against the wall as as he registered the sensations from both his tail and his dick.

"Feels amazing, doesn't it?" The Demon King chuckled. Right as Rin was about to ask him what he was doing, he felt a sleek fur of Mephisto's tail slide down the back of his pants and toy with his entrance. He bucked his hips again, letting out a mewl. The tip of the tail circled the entrance a few times before carefully pushing in. "Ahah~!" It didn't hurt, but he wasn't used to the sensation either. Mephisto kept his tail there for a moment to let Rin adjust before starting with slow thrusts. Rin started jacking himself off with his tail at the same time and holy shit, it was amazing~!

He clung onto Mephisto and Mephisto's arms still held him up against the wall as they pleasured each other and themselves. Rin could feel that heat building below his stomach, could feel it coiling like a spring. He rocked his hips back onto Mephisto's tail and forward into his own tail and the movements pushed the fur just the right way and God, he was gonna lose it soon.

"Say my name Rin." Mephisto demanded. Rin was too caught up in his own pleasure to comply. Mephisto growled and ran his claws against the grain of Rin's tail while just barely scratching the skin underneath. Rin arched, eyes rolling to the back of his head as he came over his own tail. "Samael~!" He cried, body trembling at the feeling of the claws on his tail in such a way as he released, hot cum spilling over the sleek fur of his tail. Flames flared to life around his body in a burst of brilliant blue radiance.

Mephisto growled louder and bit that spot on Rin's neck that made the half-demon whimper, clutching onto the Demon King. The action milked him of a few more spurts and made him tighten around the tail still inside him, drawing deep shudders from Mephisto as he came as well.

Rin whimpered again at the feeling of Mephisto licking up as much blood spilling from the bite wound as he could while he pulled his tail out of the half-demon. Rin knew he was doing his best not to just devour the rich liquid. Mephisto took the weak noise as a sign that they were done and began to pull away from his neck, but Rin pushed him back with a hand to the back of his head.

"It's okay this time. You can keep going." He breathed. Mephisto let loose a purr-which Rin answered with his own-and bit down all the way, fangs sinking into flesh and muscle and locking in, keeping Rin from moving. It was one of the more predatory instincts demons had. Mephisto drank the blood from the wound and Rin gasped at the feeling, his dick giving a twitch in his soiled pants.

Instinctive things weren't all that bad, as he was coming to learn the more time he spent with Mephisto and Amaimon.