Luminescent

Etiquette

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.