The Corinthian
A dream construct made to be a black mirror to reflect everything about itself humanity will not confront.
Where is he from?
The Corinthian is a character created for Neil Gaiman's comic opus The Sandman, introduced during the Dollhouse arc from issues 10 to 14, published between November of 1989 and March of 1990. He would go on to appear again in the series, as well in several spin-offs. If and when this series is ever adapted, the Corinthian will likely appear in later seasons or sequels, but when he does he's going to be f-ing terrifying.