Board Thread:Writer's Workshop/@comment-24038243-20150429132049/@comment-24450775-20150429142837

The medival age was from the fifth to the fifteenth century, so if you are going for clinical feel I would specify a centur rather then saying medival times, unless this is a first person narrative. If that's the case then you need to change the tone drastically.

If they knew about it all this time it would be recently confirmed to exist, not discovered.

I would call it a humanoid, rather then saying it looks like a human. Especially since its appearance is obscured. Ditto on its sex for the same reasons, unless you can give an in-universe reason for it having a perceived sex.

Don't say "demon-like" unless demons are confirmed creatures in this world. I say that because again, you seem to be going for clinical, and demon-like just kills that. You could call them bat-like. Demons are generally portrayed as having bat-like wings.

Whitix covered the Slender/pop culture issues, so skipping that. I will say the description in the second paragraph is redundant. You could just add the part about shadow people to the first paragraph.

I don't want to nit pick here, but there is an awful lot of description for something whose appearance is obscured. The part about how he holds his arms is kinda unnessary, and again, pop culture. I would ditch the cape too. It makes him sound like a self-insert character.

Humanoids aren't easy to do without comming off like pre-existing creatures. Especially supernatural ones.