In December 2025, LiTMUS and Japanese gaming YouTuber Yoshinama launched their single-player monster raising simulation game, Mamon King. This marked an unusual yet successful collaboration, with Yoshinama co-funding the project by investing approximately $160k USD from his own funds.
The game quickly gained viral popularity, selling over 60,000 copies in its initial week. This success enabled Yoshinama to recover his entire investment within just one month.
Yoshinama recently shared a video update discussing the game’s current status and sales figures. He announced that Mamon King will receive a physical release for the Nintendo Switch 2, scheduled for Japan on October 8.
In the video, Yoshinama disclosed that Japan’s major video game company Koei Tecmo is partially involved in distributing Mamon King’s Switch 2 version. Koei Tecmo, known for franchises such as Nioh, Ninja Gaiden, and Atelier, also worked on the Monster Rancher series, which heavily influenced Mamon King.
“Isn’t that incredible? I’m deeply honored. It truly feels like they’ve officially recognized [Mamon King] as a work inspired by Monster Rancher,” Yoshinama remarked.
Regarding Mamon King’s future, Yoshinama noted that the game is steadily approaching 90,000 copies sold. Beyond recouping the full $160k USD investment, the game has generated approximately $12.6k USD in profit, which Yoshinama plans to allocate toward his next project.
In January, Yoshinama mentioned his intention to begin production on his next game around a year and a half later, with plans to announce it roughly three years from then. Yoshinama already has a clear vision for the next game, describing it as “significantly better and more developed” than Mamon King. With sufficient funding now available, it will be intriguing to observe how a potential Mamon King sequel or an entirely new intellectual property evolves moving forward.