I'm just curious why he couldn't tell anyone about the demon seed or whatever?

Cause they think Devils are a myth or something.

But there are devil worshippers? At least his boss knows about the devils, right?

Minor spoiler

From my understanding, the public knows that djinns got their demonic powers from the mental(?) realm. There are no demons on earth at this time. The concept of a Devil existing on earth is what is absurd to them. I remember reading from the novel where the public acknowledged the existance of Devils only when presented with evidence by a high ranking hero. There was even a line that said 'Nayun was surprised that such a thing as a devil exists'.

I seee. Gotcha. Ig so far there's no real devil on earth yet.