About:

A creature made of pure evil... Or that's how his kind is written about in tomes of old. Truth be told many of these demons must procreate, they are not immortal or special.
Bog demons prey on foolish wanderers through swamp grounds or dense, humid forests and jungles. Bogs are their most common nesting grounds, thus the name. And though they really aren't demons, a good way to describe their tumultuous history among humanity is that they are truly parasitic in nature, their species name a given classification rather than one of their own (of which they do not do, solitary at birth and learned through precise natures in evolution).

Autclavius in particular takes his own name. These creatures rarely, if ever, give themselves one, so he is quite proud of his sly mind and charming appearance. Despite being a bog demon, he is a very haughty man, thinking of himself as the pinnacle of his species that others of his kind could strive for.
But it doesn't matter too much how debonair he finds himself, as he still is one of his kind. His life isn't grand or special, and he always needs to feed to keep surviving-- he is incredibly aggressive without provocation, mostly due to his constant hunger for humanoid flesh that drives him.
When he's in a good mood, he actually doesn't mind having a chat with other creatures... Rarely do humanoids find the pleasure since their meat is desired so.

He appreciates having a large swath of forbidden wood and bog to himself, 'overseeing' it and taking great care to stay the sole master of this small (in the grand scheme of things) realm. He doesn't venture beyond what he owns.
As most bog demons, one rarely ever sees his face if facing him. In fact, he doesn't really need his eyes, as a tactile creature. His sense in shallow water is amazing, most of all.
He is incredibly allergic to hay and ash and it's easy to ward him off with a swing of a torch. Luckily for him, these are unresearched methods and are his big secret to keep as long as he can help it-- he steers quite clear of nosy trekkers and researchers who come prepared in that manner.

Notes and trivia:

• His name is pronounced like ought clay-vee-us (said quickly)
• If it isn't obvious, his neck/torso opens up to feed on large animals and people
     Humanoids are vastly preferred to creatures, as their meat and blood is more sustainable and healthful than animals among his species.
• The wings are optional!