The Case Book of Arne

Lore & Background

The story is set in Lügenberg, a city where supernatural beings and humans coexist. The protagonist, Arne Neuntöte, is a young vampire with supernatural powers who runs a private investigation office specializing in occult cases. Despite his youthful appearance, he is an experienced detective handling requests involving curses, monsters, and unexplained phenomena. He works alongside Lynn Reinweiß, the daughter of a human nobleman with a strong interest in vampires, who becomes his assistant after a chance encounter. Together, they investigate interconnected cases involving ghosts, werewolves, witches, and other supernatural entities tied to the hidden history of the city.

Reader's Guide

The Case Book of Arne originated as a freeware game created with RPG Maker, reflecting the indie game development scene of the late 2010s. Its success led to a manga adaptation illustrated by Soraho Ina, serialized in Media Factory's shōjo manga magazine Monthly Comic Gene from November 2018 to March 2022, collected in four tankōbon volumes. A second manga adaptation based on the anime began serialization in January 2026. The anime television series, produced by Silver Link, aired from January to March 2026 on Nippon TV's AnichU block and other networks, with Crunchyroll streaming it and Plus Media Networks Asia licensing it for Southeast Asia. The series features an original anime character, Louis Hartmann, voiced by Mariya Ise, forming a trio with Arne and Lynn. The franchise's expansion from freeware to a full anime adaptation demonstrates the potential for independent game projects to gain broader media attention.

Did You Know?

• The game was created using RPG Maker and originally released as freeware in November 2017.
• No anime adaptation of the game has been confirmed or released.
• No official soundtrack has been documented for this freeware title; claims of opening and ending themes are unverified.
• No second manga adaptation based on an anime has been announced; only one manga adaptation exists, serialized from November 2018 to March 2022.

Origins & Production

The Case Book of Arne began its life not as a polished commercial product but as a freeware title crafted by the solo developer Harumurasaki (also credited as Murasaki), with character designs by Harutarō. Built on the RPG Maker engine, the game first saw the light of day in November 2017 through the Vaka Game Magazine website, a platform that gave independent Japanese game creators a venue to share their work at no cost. Despite its modest freeware origins, the title found a broader audience when it became available on Steam, where players could access it in Japanese, Chinese, and English. This multilingual availability helped the Gothic horror mystery adventure game reach international audiences who might not have encountered it through Japanese web channels. The combination of Harumurasaki's narrative vision and Harutarō's visual style established a distinctive aesthetic that would later carry over into the franchise's manga and anime adaptations, proving that a single creator's RPG Maker project could grow into a full multimedia franchise spanning multiple languages and platforms.

Plot & World-Building

The story unfolds in Lügenberg, a city where the boundary between the natural and supernatural has long since dissolved. Humans and otherworldly beings share the same streets, and it is into this world that Arne Neuntöte operates. Though he appears young, Arne is a seasoned vampire detective who runs a private investigation office focused exclusively on occult cases—curses, monsters, and unexplained phenomena that fall outside the jurisdiction of ordinary law enforcement. His work takes a new turn when he crosses paths with Lynn Reinweiß, the daughter of a human nobleman whose fascination with vampires leads her to become his assistant. Together, the pair dives into a web of interconnected mysteries involving ghosts, werewolves, witches, and other supernatural entities. What begins as individual cases gradually reveals a deeper thread: the hidden history of Lügenberg itself, suggesting that the city's supernatural present is inextricably bound to a past that its residents have worked hard to bury.

Manga Adaptation

Following the game's initial success, the franchise expanded into print with a manga adaptation drawn by Soraho Ina. The series ran in Media Factory's shōjo manga magazine Monthly Comic Gene, with serialization beginning on November 15, 2018, and concluding on March 15, 2022. Over that span of more than three years, Ina's chapters were gathered into four tankōbon volumes, the first released on April 27, 2019, and the final volume arriving on March 26, 2022. The manga's placement in a shōjo publication gave the Gothic horror mystery a readership that extended well beyond typical game and seinen demographics. The franchise's manga presence did not end there. A second manga adaptation, also illustrated by Ina, was announced to follow the anime adaptation's episodes. This second serialization launched on Bushiroad's Comic Growl website on January 7, 2026, effectively creating a parallel manga track that mirrors the animated series for readers who prefer the printed format. Both manga runs showcase Ina's ability to translate Harutarō's original character designs into a sustained narrative medium.

Anime Adaptation

The anime television series, announced on November 6, 2024, marked the franchise's most ambitious expansion to date. Silver Link handled production under the direction of Keisuke Inoue, who also shared series composition duties with Harumurasaki. Episode screenplays were split among Aya Matsui, Hitomi Ogawa, and Akira Nishikubo, while Akiko Satō took charge of character design based on Harutarō's original artwork and simultaneously served as chief animation director. Yoshiaki Fujisawa composed the score. The series aired from January 7 to March 25, 2026, on Nippon TV's AnichU programming block alongside other networks. For international audiences, Crunchyroll secured streaming rights, and Plus Media Networks Asia licensed the series for Southeast Asian broadcast on Aniplus Asia. The opening theme, "Q.E.D.", is performed by Sou, while the ending, "Ningyō no Machi" (Doll Town), is sung by Watashi Kobayashi. Notably, the anime introduced Louis Hartmann, voiced by Mariya Ise, as an original character who joins Arne and Lynn to form a case-solving trio, expanding the core dynamic beyond the source material.

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