Spicing up a Humanoid Abomination

So I'm writing a story where one of the villains is supposed to be the child of an Outer God and a human. The thing is, my character is very plain, especially compared to characters like Wilbur Whateley or his brother. If you met him, you'd think he was a normal looking person with some weird birthmarks. Bear in mind this is his default form. This isn't a disguise that hides a much more hideous form. I'm wondering what a being that's half-Outer God should look like, or is there a way this character can work as a Lovecraftian being? One idea I've been thinking about is that this character's internal organs are very atypical. Any idea what an Outer God should look like if you cut them open?

To me, a Humanoid Abomination is either a Eldritch Abomination dressed up as a human being or at least somewhat humanoid in appearance. It seems your character is neither, but then again I might have too narrow a view on this.

The internal organ-thing would be more Bizarre Alien Biology than anything else, but I suppose it works as a more subtle way to make a character alien, if not necessarily 'eldritch'. If cutting them open resullts in a fountain of black, acidic blood shooting fourth, you've got a good indicator you're not dealing with anything normal, though I'm kind of missing the 'eldritch, mindshattering horror' here. If there would be far more blood than the body could possibly contain, for instance, things would start to get comfortably weird.

I think Humanoid Abomination could look pretty much like a human, but if it doesn't have an effect on other people or animals, then I'm not sure that it actually counts as Humanoid Abomination (it needs that "abomination" aspect). As far as physical traits go, though, a strange birthmark, or weird fingerprints or irises, could mark this character as not-completely human.

I guess my problem is what I want this character to be something that wouldn't be out of place in the Cthulhu Mythos, kind of along the lines of Wilbur Whateley. While a weird birthmark could qualify someone as a Humanoid Abomination in some works, it seems rather tame when compared to the Cthulhu Mythos.

If he has the power to undermine people's sanity in a way that they can't understand, then he will be quite impressive regardless. His ordinary appearance could then become potentially more creepy than any clear outward disfigurement could ever be. Think "Norman Bates" with supernatural powers.

Less is more; don't go for out-and-out Body Horror. I think a Humanoid Abomination should look like a normal human (outwardly) but have some odd features/traits/characteristics that push it firmly into the Uncanny Valley. People who interact with him are subtly creeped out, but can't quite put their finger on why. (Hint: it's because he's a Humanoid Abomination, but they don't know that...)

In The Hitchhikers Guide To The Galaxy, the alien Ford Prefect was described this way:

edited 9th Apr '17 6:19:54 PM by pwiegle

I know this is an old thread, but what is the line between a Humanoid Abomination, or any abomination for that matter, and just an odd human. I get that the idea is that an abomination is supposed to drive people insane, but I always assumed that was because they defy what is know of the natural world. So why wouldn't someone with unusual internal organs count as a Humanoid Abomination?

An abomination is something to be warned of.

Just make it a character who ruins things, intentionally or not. Hell, if it's unintentional, it adds to the "human" aspect.

After I started this thread, I looked at other threads that asked similar questions. Many people believed what made something an abomination was its mentality. Something that has an alien thought process or morality system, would be considered an Eldritch Abomination, especially if it views humanity as insignificant.