~In the LostFell universe~ (Underfell lostlie)

Fuego: *Pacing around angrily* That IDIOTIC SELF-HAPPY BASTARD! NEXT KING OF HELL MY ASS! I SHOULD'VE BEEN THE NEXT ONE! 

Ariel: For one, he was the one Severus decided to keep... *Reading* 

Fuego: But why couldn't it have been ME?! THAT BASTARD HAS TORMENTED ME! TEASED ME! I BET HE'D GLADLY ABUSE ME IF HE HAD THE CHANCE!

Ariel: *Turns a page* You did rape him, didn't you?

Fuego: AND THE FUCKER ENJOYED IT!

Ariel: *Cocks a brow, looking up at him finally* Didn't you?

Fuego: *Choked noise* ! *Glares at him*

Ariel: *Shrugs and keeps reading* I'll take that as a yes then.

Fuego: *Blushes furiously*

-Hell-

Chresta: *Sitting with an open book in front of him, drooling slightly, his pupil a heart as he daydreams of his "encounter" with Fuego*

Severus: Geez, can't you focus on your studies for once?

Chresta: Hehe~ Sorry, not sorry. Just can't help but think about yesterday~

Severus: Huh?

Chresta: Let's just say a hottie took my cherry~

Severus: Get yourself together. Right now. 

Chresta: Fine~ But give a few hours to myself afterwards~

Severus: Pervert. *Goes off to do his duties*

Chresta: *Purrs* Oh Fuego~ Can't wait for our next encounter~ *Goes back to reading*

~Explanation~

Ariel, Sev and Xans do love each other in this AU, though Severus spends far most time by himself. However, when they all are together, sex is very likely to be the first thing to happen. Severus is a very sexually driven demon, and doesn't mind a few quick rounds throughout the day, even if Xans may.

Chresta and Fuego on the other hand, are more complicated. 

Chresta tends to act very perverse and often wears clothing revealing at the very least his collarbones. He doesn't mind suddenly being dragged aside and fucked into submission by a certain other demon skeleton. He studies to become a ruler, however, and doesn't mind the pressure Severus puts him under, as long as he can get some time to himself every now and then.

Fuego, however, is jealous of Chresta. As Ariel took him with him, he lives in the underground where his existance hardly matters. And even if he hates his half-brother, Chresta easily turns him on, by sending him nudes and other suggestive images when they're alone. He even once formed a whole female ecto-body, and boy did Fuego need some time to releive himself after that. Fuego usually responds in a very pissy manner, and often rants about his brother to Ariel, who over time has learned not to take it seriously. 

I hope you enjoy these guys~