Game company LiTMUS and Yoshinama – a popular Japanese gaming YouTuber with over 1.04 million followers – will release the single-player monster raising sim Mamon King on December 11 for PC (Steam) and Nintendo Switch.
Unusual for a YouTuber collaboration game, Mamon King’s development was co-funded through the personal investment of Yoshinama, who caused a good deal of buzz online after announcing to his subscribers that he’d taken out 25 million yen (over $160 thousand USD) from his savings to complete the game. To find out more about the project, AUTOMATON Japan recently talked to Yoshinama and Yu Totsuka, the game’s director at LiTMUS.
Featuring a monster raising system and turn-based tournament style battles, Mamon King draws inspiration from Koei Tecmo’s Monster Rancher series. The project started around two years ago, and according to Yoshinama – the idea of making the game just came over him like a sudden impulse he simply had to follow. “One day I just thought, ‘I want to make a game,’ and started working on it.”
But despite his years of playing video games in front of thousands of spectators, Yoshinama was a complete beginner when it came to actually making them. “When I consulted with Totsuka about the project, I remember thinking wait, that’s how much money it takes to make a game?” Still, even after hearing from LiTMUS that the project would not only be expensive, but that he’d have no guarantee of it being a success, Yoshinama didn’t feel like giving up.

“People might think I’m weird, but I was like, ‘I want to make a game. I don’t need profit.’ Honestly, I think turning a profit from this would be extremely difficult. I have zero track record in game development and no credibility in the field; I’m just a streamer. Even so, I desperately wanted to make a game.”
This attitude of Yoshinama’s was also what ultimately got LiTMUS on board. Totsuka admits that among several candidates his company was considering, Mamon King was initially low-priority due to its niche genre and proposed scale of development. But after hearing that the YouTuber was still determined to see the project through despite the risks, Totsuka decided to join forces. “I was honestly moved by his statement, Even if sales are tough, I want to make what I want to make (laughs).”

Interestingly, he explains that Mamon King’s development is quite different from typical collaboration games co-developed between companies and famous content creators. While it’s common for the development company to offer a pre-existing template or game format which the streamer will give some input on, it’s rare for them to have much creative freedom. On the other hand, Mamon King is a completely original game being developed from scratch, with Yoshinama acting not only as a producer but as a game designer. This is also why he decided to make such a big personal investment in development.
“The most effective way to make Yoshinama’s ideal game, taking into account things like budget, was to also have him invest in it. If both sides took an appropriate risk, we could perfectly build what he’d envisioned. I’ve seen projects fail when companies try to minimize a creator’s risk while promising to fulfill their wishes. With that lesson in mind, I had Yoshinama invest, and in exchange, we committed ourselves fully to the project. It turned out to be the best approach,” Totsuka explains.
Now that Mamon King’s release is just around the corner, Yoshinama is incredibly happy he took the plunge. “Developing a game in parallel with my streaming was extremely hectic, but I always felt happy during development. It was so much fun, so even if Mamon King turns out to be a monumental flop, I think I’ll want to make something again after a few years.”
Mamon King launches December 11 for PC (Steam) and Nintendo Switch.



