Srajo "The Obscure", is a legendary white whistle delver of The Abyss. Since he's a white whistle, he's presumed to have made amazing discoveries within the pit and retrieved artifacts that have changed the world. Like most white whistles, he settled on the 5th layer and lived there for some time, since it is the last point of the abyss where it is possible to return alive.
He's also known as the "Lord of Mystery", and true to his epithet, is the white whistle with the least amount of information known.
The Lord of Mystery is an enigmatic figure, shrouded under a cape and hiding his face behind a mask that resembles a plague doctor mask with three holes.
Basically nothing is known about his personality, however the fact that he was seemingly comfortable living in the harsh environment of the 5th layer purely due to personal interest suggests that he's single-mindedly focused on the abyss.
At some point and for unknown reasons, Srajo decided to take his "Last Dive" and descended to the 6th Layer of the Abyss without even mentioning anyone else, Bondrewd being the only one that was made aware of his decision. As such, he's currently at least in the 6th layer in some unknown location.
Since he's a delver that attained the extraordinary rank of a white whistle, he's presumed to be an extraordinary individual. Much like his peers, he's able to descend to the 5th layer seemingly without much trouble, as he was living there, and is most definitely equipped with one or more 1st grade artifacts that greatly enhance his delving abilities.
His appearance was inspired by plague doctors.