Kurokosagi Jingai-san to Kenkyuuin-kun.

Kurokosagi Jingai-san to Kenkyuuin-kun is a manga series written and illustrated by the artist known as renG。 that began serialization in the late 2010s. The work belongs to the fantasy-comedy genre, focusing on the unconventional daily life of a researcher who finds himself in an intimate domestic arrangement with a mysterious, supernatural creature known as a jingai. It emerged from a broader niche of Japanese web-manga and serialized anthologies that explore non-human romantic or companionship dynamics, emphasizing surrealism and character-driven humor over traditional narrative structures.

The aesthetic of the series is defined by renG。's distinctive character designs, which contrast the mundane appearance of the human lead with the elaborate, often abstract or monstrous visual representation of the non-human partner. The series was designed to appeal to readers interested in character-based fantasy, often utilizing a sketchbook-like art style that highlights the emotional connection between the pair. While primarily a digital-first or serialized publication, it garnered a devoted following within its specific subculture for its unique take on the 'creature companion' trope.