Nyarlathotep (ニャル子?) is the main protagonist of the anime, manga, and light novel series and the main hero of the visual novel game. He's an Outer God who is sent by Azathoth to protect Mahiro Yasaka. Nyarlathotep is an outer god. He is sent by the Outer Gods to Earth in order to protect a human named Mahiro Yasaka. Nyarlathotep quickly falls in love with him though which he refers to as "love at first sight". His feelings towards Mahiro become serious with him going so far as eventually talking about marriage and a family together. He takes the form of a human girl with long silver-colored hair, but says to Mahiro that he can change to her original form if he wants him to.His actual age is unknown since he always stops Mahiro whenever he becomes curious or questions his age. When it comes to education he stated to Mahiro that he is a being of infinite knowledge and wisdom, spawn from the blind idiot god Azathoth himself, who's dream we all live in and who's mercy we are all at, and it is insulting that a mere mortal would ask such a pitiful question. He joins Mahiro at his school in order to get closer to him. Nyarlathotep is shown to be highly into gaming, and says that Earth's entertainment is well known to the outer gods.
Nyarlathotep is an indescribable Alien God that can take the form of anything he desires
She is always friendly to Mahiro, eager to pursue him, but often shows abusive and brutal habits to any hostile aliens. She is also obsessed with otaku culture. She takes the name Nyaruko Yasaka as Mahiro's cousin when staying at Mahiro's house and attending his school. Her actual age is unknown since she and Kūko always stop Mahiro whenever he becomes curious or questions her age, although she states that she has already graduated from space college. She happens to be smart and self-confident, as she graduated from one of the best universities at the top of her class, and entered the Space Defence Agency after her exam. She is also quite wealthy, capable of spending a lot on otaku-related products. As a top agent, she mainly uses space CQC to fight (note that the definition of "space CQC" is defined by the user and is not restricted to close quarter combat weapons). She claims to be one of the best fighters on Earth, as she states that her combat level is 530,000, while a normal farmer armed with a hunting rifle is 5 (though this may be a parody of Dragonball Z). Despite this, she is always unsuccessful when dodging Mahiro's fork attacks. She shows fourth wall awareness in the first episode of the second season of the anime.
It has been shown that Nyaruko can easily irritate Mahiro with her action and word she uses. It is obvious that Nyaruko has a crush on him due to the fact that she sometimes has perverted thoughts that involve Mahiro.
Ever since Nyaruko confessed to Mahiro that she was in love with him, her presence around him can sometimes fluster him. As time goes by, the two of them spent more time with each other. Mahiro began to grow attracted to Nyaruko as a woman.