Koumuin, Nakata Shinobu no Akutoku (公務員、中田忍の悪徳) is a light novel series written by Tachikawa Uraura and illustrated by Ouchi Kaeru. It ran from 2021 to 2024 with a total of 8 volumes under the GaGaGa Bunko label. I currently read 6 volumes, but I plan on finishing it up soon.

The story follows the life of 32-year-old Nakata Shinobu, the head of a support section of the city welfare life department. He encounters a mysterious "elf" girl (everyone calls her "Isekai Elf" at first) in his apartment and has to work through various hoops to understand where she came from and how to send her back. The girl is unable to speak Japanese, which only makes this even more complicated.

Shinobu is a responsible, honest, strict, and extremely unfriendly person as he doesn't seem to show any emotion to the people around him. He is also extremely prone to follow "protocol", which causes lots of comedy moments. For example, he was ready to kill the Isekai Elf and himself to prevent possible pathogens from destroying Japan, only to be stopped by a few acquaintances.

The huge gap between Shinobu's strictness and the cheerful and childish elf is one of the main points of the series. Shinobu basically has to navigate what it means to be a parent: teaching her to read, giving her a name and a purpose, and monitoring her so that she doesn't do dangerous things.

Shinobu can come across as quite annoying at times with his "I am the adult in the room" attitude, but that is part of his character so it is hard to judge the situation too harshly. He does get more "malleable" over the course of the volumes thanks to the influence of Yuna and Ariel.

The main characters of the series (aside from Shinobu) are:

Isekai Elf / Ariel

A cheerful girl coming from another world. She ended up being called Ariel because she heard the word "arieru" (possible/likely) in Japanese and started repeating it multiple times. She acts like a kid even though her body looks to be around 18-ish in age. This is related to her stay in the other world, which is revealed as you read the story. She has some special magic too which she can use at will.

Yuna Ichinose

A coworker of Shinobu. She is a talented but usually a bit lazy woman. She serves as the voice of reason together with Naoki whenever Shinobu starts to do something crazy due to his strictness. She has started to feel attraction to him as the story goes along.

Yoshimitsu Naoki

An old friend of Shinobu. He helps them discover more about Ariel's identity with his connections at the university. He is generally a grounded and reasonable individual, even though Ariel is scared of him due to one event at the beginning of the series.

Tamaki Mihara

A high school girl who felt estranged from her peers due to her mature body. She is the first friend of Ariel and they are often playing together. She looks up to Shinobu and feels attraction to him, though he only treats her as a kid.

My favorite character is Yuna as she is the "grounding" that Shinobu needs to live a more normal life away from his strictness and rigidity. She also acts as a "mother-like" figure to Ariel during her stay and is generally the one who moves the story around the most in the important moments.

The last volume I read (Volume 6) ends with a big cliffhanger as Tamaki seems to be plotting to use Ariel's power to do something unsavory. I am sure it will be thwarted, but I am curious to see how this ends up concluding. Nakata is strict, so maybe he could block all communication with her?

I am really curious to see how it ends. The story may be leading to Shinobu ending up with Ariel as she is now way more adult in personality and behavior, but I still feel Yuna would be a better match for him. I guess I will see once I read the last two volumes...