Darn it, I hoped I'd deleted this in time.
Okay, the meds are kicking in, but I feel compelled to answer this.
The book example is that the more bizarre Call of Cthulhu monsters don't really see people as something to be moral over. We're like ants, or blades of grass, even if we're actually similarly sized creatures.
Rich is clearly playing with the book example on this matter, so it's not reliable, which is why I deleted the post. I think the more important point is that the Protean is listed as chaotic neutral, and not only does Xykon assume it should be more evil, but its story arc is projecting it towards good.
Whatever insight Rich had to realize that an omnicidal Chaotic Neutral being is just a few hugs away from being a friend of paladins, it is easier to have that insight for a monster without any alignment at all, and described mostly as following other people's orders.
I'm still here to show that the Protean is not the best fit, not to show that the Hunting Horror must be the answer, and in this area, the Hunting Horror fits more than a Protean.