Well Nyarlathotep has basically been very busy in Hyboria. He was the one whispering in the Atlantean queen’s ear that she could worship other gods when her god Valka stopped listening and Atlantis fell.
About the Entity and Khitai it is a bit more vague as to Nyarlathotep’s involvement. but the rare boss in Enigmata of Yag is called The Spawn of Nyarlathotep and he does sort of celebrates how the Entity is now causing havoc in Khitai.
His involvement with the Serpent men is about the Serpent men is cast out by their God Yig due to them starting to make experiments on themselves to get supernatural or alchemical powers. In Coils of the Ubah Khan you encounter their experiments such as the Bio titan.
So The serpent men starts praying to Nyarlathotep asking him for powerful gifts and he gives them the Shining Trapezohedron (A powerful artifact which can open portals to other dimensions) .
Well Nyarlathotep is basically Lovecraft’s version of the Devil or Loke or the Joker A trickster who loves to toy with humans (and serpent men), he brags to the player about how he has set all these events in motion all over Hyboria and he is happy to give everyone powerful weapons and artifacts if they want them.
Seems like he enjoy watching people use this powerful stuff to “blow themselves up or others”.
Btw. did you know that if you are playing a Hox at the entity boss fight then you will get a special message from the entity because you serve another elder god (Xotli) ?
Also, if you jump into the abyss at the Little Prince boss in Vile Nativity you will get a special “Cthulhu message” in your chat box.
Also the ghosts outside Vile Nativity will sometimes talk about the little prince is dreaming of R’lyeh.
Oh, and the Custodian of Yoth boss in Sepulcher of the Wyrm is also some sort of elder being (not a god) but one who is actually keeping the portal to Yig’s domain sealed so when you kill it you actually let Yig into this world
Oh I forgot. to answer your question about the Entity. He is a lovecraft inspired being of funcom’s creation. He seems to be related to the Yag Kosha aliens from Tower of the Elephant and they had some sort of civil war on their own planet so those who opposed the entity fled to Earth (Hyboria) and the Entity and his followers came here as well and landed in khitai creating that Crater in Kara Korum.
As for the Lurker in house of Crom. That is one of Lovecraft’s elder god’s called Yog Sothoth aka The Lurker at the threshold. If you pay attention to the whole story about House of Crom explained in the quests inside HOC you will find that funcom more or less adapted Lovecraft’s “The Dunwich Horror” into aoc.
The Queen getting pregnant with the Yog sothoth’s child is basically the same as the story of the Dunwich horror.
In aoc, the little prince is the same as the Wilbur waitely, the child of Lavina waitely. and same thing happens, the child grows into this tentacled monster.
Aaaaand I am spent! for now
might have forgotten some details or whatever. I am sure someone will be eager to correct me
ps. will come back with a mention about Nyarlathotep and the T6 raid. short version. t6 and it’s story is an adaption of the Conan and the Emerald Lotus novel