The series' twelve volumes were published by Soft Bank Creative under their GA Bunko imprint between April 2009 and March 2014.

Nyaruko-san centers around Nyaruko, a formless Lovecraftian deity of chaos (Nyarlathotep) who can take on the shape of a seemingly cute silver-haired girl.

Mahiro Yasaka is a normal high school boy who is being chased by a fearsome black alien one night, until Nyaruko saves him.

Aliens find Mahiro and the Earth strangely attractive, for entertainment, auction, or resources.

Eventually, Nyaruko and two other Lovecraftian creatures, Cthugha and Hastur, end up being freeloaders at Mahiro's place.

[2] Mahiro has become accustomed to his protection detail of Nyarlathotep (Nyaruko), Cthugha, and Hastur making his life fascinating.

Nyaruko-san began as a light novel series written by Manta Aisora with illustrations by Koin [ja].

The series, spanning twelve volumes, was published by Soft Bank Creative under their GA Bunko imprint between April 15, 2009, and March 17, 2014.

Nyaruani: Rimenbā Mai Rabu(kurafuto-sensei)), also produced by DLE and directed by Azuma Tani, aired 11 episodes on BS11 Digital between December 11, 2010, and February 26, 2011.

An anime television series produced by Xebec aired in Japan between April 10 and June 26, 2012.

Nyaruko-san illustrated by Kei Okazaki was serialized in Shueisha's Miracle Jump magazine from May 6, 2011 to April 10, 2013 and was compiled in two volumes.

[20] The game's story is based on the first season of the anime television series, with some additional content.

Aiden Foote from THEM Anime Reviews gave the first season (Nyarko-san: Another Crawling Chaos) a 3 out of 5 stars rating.