This gem surfaces soon
We have it ready, but it is not unsealed yet. Come back when it opens.
Opens on 2026-07-10 (JST)
You spend SP to unleash your Mamon's signature skill. Your opponent can just take that SP for themselves instead, and now it is their move.
A single-player monster-raising simulation developed and self-published by LiTMUS Co., Ltd., a Tokyo studio wholly owned by the talent-management company UUUM. You summon and raise a Mamon, training it with kindness and sometimes strictness, across three cycles instead of the usual two: day-to-day raising and joint drills with rival Mamon, a dice-rolled expedition into unexplored land where random events can boost a stat or upend your plans, and 1-on-1, turn-based command battles where every skill costs SP, and either fighter can drain the other's pool outright. It is the debut project of Yoshinama, a popular Japanese gaming YouTuber, who spent roughly two years and 25 million yen of his own money building it after LiTMUS took notice of his commitment; asked directly whether it is an homage to Monster Rancher, which he has repeatedly cited, he confirmed it outright, and per that same interview obsessed personally over tuning training success rates and random-event odds against his own hundreds of hours of playtesting. Released in December 2025, it is Very Positive at 90 percent over 605 reviews, and while AUTOMATON WEST has already covered its launch, only about 11.4 percent of those reviews are in English so far, so its reach beyond Japan is only just beginning.
Published 2026-07-10
01First, the one feeling
- The expedition is a dice roll into land no one has trained for: advance along its branching route and a random event can hand your Mamon a stat you never trained for, or just as easily strip away a stockpile of SP you had been saving for the fight at the end of it, so every roll carries real upside and the same risk of undoing exactly the training you spent the last cycle building.
- Every skill in a fight draws down a shared resource, SP, and it is not only yours to spend: your opponent's move can drain it straight out of your pool before you get to use it, so a battle is never just picking the strongest attack, it is deciding whether to spend now, hold, or gamble that the enemy will not reach for your reserves first.
- Training, expedition, and battle keep handing off to each other rather than looping in place, so a skill your Mamon only picked up by surviving a bad roll out in the field becomes the exact move that turns a losing command fight around, and the next raising session already has a new reason behind it.
02Who this is for (and who it is not)
For you
- You love Monster Rancher's raise-then-battle taste, and want a developer-confirmed homage that adds a third cycle on top, a dice-rolled expedition where random events reshape your Mamon before it ever reaches a fight
- You want the SP economy of the battles themselves: every skill draws from a pool either fighter can drain, across 38 distinctly designed Mamon and more than 170 evolving skills, tuned personally by a developer who obsessed over its probabilities
- You want to catch a genuine Japan-side debut early: a YouTuber's first game, self-funded for about $160,000, Very Positive at 90 percent over 605 reviews and already covered by AUTOMATON WEST, before its English-language audience catches up
Not for you
- You want twitch reflexes or real-time action; this is a turn-based, SP-managed command battle system built to be accessible to anyone, not one that rewards fast reactions, and it is a paid, fully launched title, not free and not in Early Access, with no AI-generated assets and nothing sexual by Steam's own descriptors
- You want a game the West has never touched; AUTOMATON WEST has already covered its launch and Metacritic has opened a page for it, so calling it fully undiscovered would not be honest. What is true is that only about 11.4 percent of its 605 reviews are in English so far, and its praise remains almost entirely Japanese-language
03The roots of this taste
90% positiveonly 605 reviews — yet almost no one has found it
Mamon King Buried gem
A single-player monster-raising simulation in which you summon and raise creatures called Mamon, training them with equal parts kindness and strictness until you can dethrone the reigning champion and become the Mamon King yourself, developed and self-published by LiTMUS Co., Ltd., a Tokyo studio wholly owned by the talent-management company UUUM. The loop runs on three cycles rather than the usual two: raising, day-to-day ranch training plus joint drills with rival Mamon that teach new skills; expedition, a dice-rolled, board-game-style trek into unexplored land where ancient Mamon lurk, its route branching through random events that can just as easily hand you a stat boost as throw a carefully built plan off balance; and battle, a 1-on-1, turn-based command fight in which every skill costs SP, tougher moves demand more of it or an even greater sacrifice, and either side can drain the other's pool outright, so timing what you spend and when becomes the whole contest. Across 38 distinctly designed Mamon and more than 170 skills that evolve with repeated use, the game is the debut project of Yoshinama, a popular Japanese gaming YouTuber making his first game, who spent roughly two years and 25 million yen (about $160,000) of his own money building it after LiTMUS's own staff took notice of his commitment. Asked directly by AUTOMATON JP whether the game is an homage to Monster Rancher, which he has repeatedly cited in past interviews, Yoshinama confirmed it outright; per that same interview, he personally obsessed over the game's probability tuning, checking and re-checking training success rates and random-event odds against his own hundreds of hours of playtesting to keep the randomness thrilling rather than stressful. Released December 10, 2025 per Steam's own listing on both its Japanese and English storefronts (AUTOMATON's own pre-launch interview and its post-launch coverage both give December 11, a one-day gap we note rather than resolve), it is Very Positive at 90 percent per Steam's own store page (546 of 605 reviews positive per Steam's review API), a paid title at $12.99 (¥1,480 in Japan), not free, fully launched and not in Early Access, with no AI-generated assets and, per Steam's own content descriptors, nothing sexual (ids: none, notes: none). It supports English and Japanese only, and while AUTOMATON WEST covered its launch, describing it as briefly topping Japan's Steam best-seller chart ahead of games like Apex Legends and Overwatch 2, only about 69 of its 605 reviews, roughly 11.4 percent, are in English so far, and Metacritic already has a page for it with no score yet aggregated, so calling this discovered by the West would not be honest. What is true is that almost all of its praise so far is Japanese-language, and its reach beyond that is only just beginning.
Give it your first passMonster Rancher The monster-raising origin
The origin of this taste, confirmed directly by the developer: Monster Rancher, known in Japan as Monster Farm (モンスターファーム), a life-simulation raising game created by Tecmo (now Koei Tecmo), first released for the PlayStation on November 30, 1997 (the Steam version, Monster Rancher 1 & 2 DX, remastering the series' first two entries, was developed and published by Koei Tecmo in December 2021). Its signature gimmick let players generate a brand-new monster by inserting almost any CD into the console, a disc-reading system Tecmo built that turned the disc's own stored data into a random seed for the creature's stats and breed, and from there the player raised it on a training schedule and entered it into official tournaments to fight, a raise-then-battle loop that helped define the genre of monster-raising sims. Asked directly by AUTOMATON JP whether Mamon King is an homage to Monster Rancher, which he has repeatedly cited in interviews, its developer Yoshinama confirmed it outright. Mamon King keeps that raise-then-battle spine, training a summoned creature called a Mamon and entering it into 1-on-1 command battles, but replaces the disc-reading monster generator with a dice-rolled, board-game-style expedition phase between training and battle, and layers an SP resource either fighter can drain onto the fights themselves, additions the original Monster Rancher never had.
Give it your first pass04Make this gem shine
If it speaks to you, check it on Steam and give it your first pass. Your push is what makes a buried gem shine.
You gave it your pass. The gem just caught the light.
05The bloodline of this taste
- Monster Rancher Root
- Mamon King You are here
- Read-and-build games another taste