Neko Demon (Sebaciel)

Has adult content I'm not going to tell y'all if you want to read it you can read it, but please be 18 or older. And please be careful. This is a fanfic of my idea like a what if?
After Ciel turns into a demon. But Sebastian takes Ciel to hell and to his manor where Sebastian is the master of many soulless things that will do anything for him. But since Ciel is a demon he still has a soul just cannot be eaten by Sebastian.
Ciel is 16 years old in this story.
Questions I asked google and this is the answers:
What is Sebastian Michaelis demon name?
Mephistopheles (also known as Mephistophilus, Mephistophilis, Mephostopheles, Mephisto, Mephastophilis,and other variants) is a demon featured in German folklore. He originally appeared in literature as the demon in the Faust legend, and he has since appeared in other works as a stock character.
What kind of demon is Sebastian?
Nevertheless, Sebastian is in actuality a callous and sadistic demon; he is ruthless when attacking others on Ciel's orders, and he occasionally puts Ciel in nonfatal danger for the sake of his own amusement.
What is Sebastian Michaelis real form?
When Sebastian was summoned in the manga, he appeared in his true demon form. In the anime, he appeared as a crow or raven accompanied by a rain of feathers. In the manga, it seems that Sebastian was summoned accidentally. Many fans seem to forget that Sebastian's true form is much more gruesome, hence why he dons the appearance of an attractive man. Sebastian's demonic form hasn't been fully revealed, but it has been hinted at multiple times. He seems to wear black stilettos, has black wings, and has many eyes.
Does Sebastian care about Ciel?
Yes, in the anime, Sebastian and Ciel very clearly care about each other. Their relationship is many-layered and complicated, and that is what draws me to it.