[STEAM] Stray Children: Why the Developer of the Game That Inspired Undertale Has Now Made a Game Inspired by Undertale

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In the fall of 2025, I had the great pleasure of attending Tokyo Game Show, a trip that also naturally included a few pit stops to meet local developers and see what they were up to. On the very last day of my trip, in the final hours just before I went to the airport, I arrived at what I desperately hoped was the Onion Games office. I was overburdened with two giant suitcases, in a foreign country, and unsure of exactly where it was. As I glanced up at the building where I thought I’d been directed to go, I caught a glimpse through a window of a silly-looking figure plastered on a wall: a man in an asparagus suit.

Yeah, that was it.

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I lugged up a flight of stairs to a non-descript door where I tentatively knocked, and was shortly after greeted by James Wragg and Yoshiro Kimura. They welcomed me inside, and gracious invited me to sit down at a little round table covered in a red and white checked tablecloth. Kimura offered me some green tea from a large bottle. I was surrounded on all sides by bookcases of manga and a deluge of Onion Games memorabilia, more than I ever imagined existed for such a small studio.

What followed was genuinely one of the most warm and pleasant interviews I’ve ever conducted, but I’m going to need you to buckle up and bear with me for a bit to understand why. Kimura is a true industry veteran, a developer on games such as Romancing Saga 2 and 3, No More Heroes, and Little King’s Story, co-creator of Moon: Remix RPG Adventure, and now-head of Onion Games, which has created a long line of very silly games such as Million Onion Hotel and ****** Bird, gained a little bit of fame globally for its Western localization of the classic Moon a few years ago, and just released a little RPG called Stray Children this year.

Stray Children is a game built upon some very, very specific DNA. To understand it, I really think you need to understand Moon, which originally came out in 1997 for the PlayStation 1, but only in Japan at the time. Moon is a goofy, esoteric RPG (Kimura will refer to it later in the interview as an “oddball” RPG) about a kid who gets sucked into a Dragon Quest-like video game, only to discover that the “hero” of the game is actually murdering innocent monsters. What follows is an upside down adventure where you follow the “hero” around, rescuing the souls of those monsters and doing good deeds to put the world right, raising your “Lv” or “Love” as you go.

Moon was a truly strange game both for its time and even now, as I discovered when I played its English localization for Nintendo Switch in 2020. Its characters follow a full seven-day-long Majora’s Mask like time schedule, instead of a soundtrack it has an in-game music player with tracks from various 90s Japanese underground bands, and its puzzles and ending are extremely difficult to sus out, even for a 90s game. It’s so out there, that Onion Games translated and printed the original manual that came with Moon and released it online, so new players wouldn’t be totally lost as to why there was a timer in the top corner of the screen and why they kept collapsing for seemingly no reason.

But strange as it is, I think Moon is truly wonderful, and I’m not the only one who loved it. Toby Fox helped bolster the game’s profile a bit when he cited it as a major inspiration for Undertale, and having played both games it’s extremely easy to see the crossover. Kimura and Fox have since met and talked about their respective games, a friendship that in turn seems to have inspired Kimura to make another RPG, which takes us to Stray Children.

At the time I conducted this interview, Kimura had just let me play the first, oh, five minutes of the game before its release. In those few minutes, a young boy with a dog-like face is visited at home by an older man, a stranger, who basically convinces him to leave his house at night and follow him to a subway station, through a secret passage, and into a room full of computer monitors. And that’s where we stopped.

Having since played the full game, I know Stray Children is about that boy getting sucked into a video game world, just like in Moon, and what follows is a really incredible subversion of Moon, which was itself a subversion of RPG tropes. While it can stand alone, I guess, so many of Stray Children’s best moments are predicated on knowing Moon, which leads to it being a really niche experience that will probably confuse some people who stumble into it. But it’s the game Kimura wanted to make, without compromise, even in the moments where that lack of compromise became frustrating.

So with that background, here’s my interview with Yoshiro Kimura, conducted over green tea and surrounded by little decals of the asparagus man and cows and various other Onion Games mascots. This was mostly conducted in translation courtesy of Wragg, though there were a few points where Kimura stepped in and gave his answers directly in English. The interview has been very lightly edited for clarity.

Yoshiro Kimura: My name is Yoshiro Kimura, the Japanese game designer. I have been developing games for more than 25 years. If I calculate from when I was 12 years old, I was making a lot of games for myself also. And now I'm the boss of the company called Onion Games and Onion Games is already 10 years old, and I spend time making indie games.

So Stray Children clearly follows from Moon, and I know you've told the story of how you ended up revisiting Moon and bringing it to Switch and bringing it to English and the rest of the world for the first time. But what inspired you to start making Stray Children?

Kimura: I wanted to make an RPG. I was thinking about making an RPG from the day we started Onion Games, but developing an RPG requires a lot of hit points, a lot of experience. And when we started the company up, I did consider doing a Kickstarter to fund it, but I'm not that famous of a game creator, so I didn't think I would get the support. So instead we went the route of making smaller games first, like Million Onion Hotel, Dandy Dungeon, ****** Bird. And we gained experience, leveled up to the point where I felt comfortable that we'd be able to, not just myself, but the team would be able to handle an RPG.

So regards to motivation for actually making Stray Children, there are several things that kickstarted the idea in my mind. Obviously one of them is Moon, but anyone who's played Moon would know a sequel to Moon isn't something that can be done. And I really like Moon myself as well, so I spent a long time thinking, "How can I make a game that has the same kind of feel, atmosphere, but without being directly connected to that game?" So once I got to the point where I could envisage the start and the end of this new story, that was when I knew we were ready to begin.

Even just from the first few minutes of Stray Children, it seems like you're exploring some of the same themes: like childhood, disconnection from adults and maybe the nature of what a video game actually is or can be. Is that fair to say?

Kimura: To answer that question, I'm going back to the motivation for making an RPG in the first place. Part of that was wanting to make an RPG, part of it was wanting to make something with the same feeling as Moon. So it goes back to memories of the games I played, my generation played, so the ‘80s, the ‘90s. Back then games that I played had a really strong influence on me. And seeing and hearing about new releases was a really exciting thing back then. That experience that I had in the past from games, I wanted to put that into Stray Children for the player to experience anew.

So for me, those games, they weren't console games so much back then, partly they were, but it was PC as well and some arcade. But if you imagine, back when I was a kid, I was living in the countryside. One day I came across this guy who lived locally and he had a C64 and PC, I don't know, '88, '98, whatever. So I'm seeing games like Ultima, Wizardry, some games on the C64, and it's just amazing seeing... It's so new to me. And also in the arcade I'm seeing Xevious from Namco, Mappy, that kind of stuff. And I loved these games and I wanted to put the feeling that I had back then into the game so the player can experience it through it.

You made Moon, oh my gosh, what, 25... More? Almost 30 years ago?

Kimura: Maybe 30 years ago.

RPGs have changed and evolved since then, so I'm curious if there's anything you've been playing in the last couple of years that has inspired you or made you think differently?

Kimura: It's a bit of an odd answer I suppose, but first recently, some stuff I've been playing anyway and I guess it has influenced me quite a lot, is I’ve been going through the first five Dragon Quest games again on Famicom and Super Famicom.

The original versions?

Kimura: The original, very hard one. And I don't know whether it's an inspiration, but I've certainly played recently, Odencat's

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.

But when I talk about inspirations, I always end up with Undertale. But before I talk about that, I want to make sure that there's no misunderstanding. So I'm quite friendly with Toby Fox and when I answer I'm answering honestly, but I don't want it to seem like I'm trying to ride on the coattails, and don't want the press chasing him for comments.

But there is an element of influence from that and I think... So Toby, he plays my games right after release, sometimes before release. But I always ask him why, why he plays and why's he enjoying them? He said, "Because I like weird, oddball games," and I thought, "Oh, well, that's the same as me." So when I thought about Undertale, Undertale's kind of weird in many ways as well. And so in talking to Toby, because we've got this common interest, I feel relaxed, a sense of reassurance. Security. I feel at ease talking to him.

One of the things that has fascinated me about Moon and Undertale and Stray Children is it feels like they're part of a larger tradition of weird, oddball games that are all inspired by one another and in conversation with one another. I put the Mother games in there, Contact.

Kimura: Yume Nikki.

Yeah. There's a bunch of them that are all playing off some of the same themes. And it's been interesting to see the conversations publicly between you and Toby Fox, where two different generations of game developers are inspiring one another back and forth. And that's a really cool thing to see.

Kimura: It's like we're kind of pen friends almost or diary friends. All these creators.

I think all game creators share this kind of feeling, whether they share it with all other game creators or there's just the oddball game creators and the fighting game creators and the action game creators, but I think everybody's inspiring and inspired by their peers.

So who all is Onion Games? How big is the team? Is it people who have been with you for a long time? Do you have any newer developers?

Kimura: So from the core development people, there's seven including myself, and we've had some younger people join recently, but they've been with us for three years, so that's the shortest. Then there's people who've been with us from the start of Onion Games, we've been working together about 11 years. And there's one of the programmers was the programmer from Chulip, so that's a long time. But even longer than that, there's a coworker from my Square days, so I've known him for 30 years or so.

You mentioned earlier you don't use this office anymore. Is everyone remote?

Kimura: So I'm the person most frequently here and one of the younger team members is often here as well. So I work here a lot. And sometimes people will come in, but generally speaking, when we're all together it's when we're drinking.

Are you working with the same composers or any of the same people who did the music for Moon?

Kimura: Yeah, basically it's the same composers. So Thelonious Monkees, which is comprised of [Hirofumi] Taniguchi-san, [Masanori] Adachi-san, and we've got [Keiichi] Sugiyami-san's doing the sound effects, so basically the same.

I interviewed them about how they composed Moon and got all those different artists together to do the Moon discs, the MDs is there anything like that in Stray Children?

Kimura: Not this time, we didn't do anything like that. That was something that we were able to do because of the team makeup of Moon itself. And I didn't think that doing the same thing again with Stray Children would have the same impact. So I wanted to go with just a straight, new composition to the game.

But we did use that, I forget what it was called in English, but the odd voice, the scrambled voice. The way we did it this time again is we got the fans of Onion Games to send in lots of... We've got fans all around the world, so speaking in their native languages, they sent us lots of voice clips and they all got mixed up and put back in. The Japanese version, I wasn't able to get it to a level that I was happy with. But with the international release, that will all be kind of like a director's cut of the odd voices.

So I saw just the very beginning of the game, but I've watched the trailers and so I have a little bit of a picture of what I'm in for, but what can you tell me about where this game goes? Especially, it seems like you're encountering people in some sort of... There's battles, but it's not a battle. What can you tell me about what's happening in Stray Children?

Kimura: That's actually the first time, in memory, that somebody's asked me that. And it's such an average and proper... Like a normal question, in a good way, that I haven't had the opportunity to answer. So give me a little time to get the elevator pitch ready.

[He thinks for a few moments.]

So it's an RPG, and as you saw with a player being sucked into the world of a video game in RPG, and in that world, as the title Stray Children suggests, there's a kingdom built by children and outside of that kingdom, outside of that land is where the adults, we call them The Olders, live. And you mentioned the battles, the battles... So underground, when you leave the safety of the *********** land, there's these creatures living underground and that's where the battles occur. But in the battles, you can fight or you can talk to the enemy, these creatures. And it's completely up to the player how they approach that.

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Is this a game where the outcomes could be impacted by how you interact with those creatures?

Kimura: That is down to the player and how they feel, how they react to the- So when talking about games, the way I feel about it is, I can tell you about the systems of the game and maybe how they work, but what occurs when you interact with those systems and the game's story, and how the game plays out, I would rather leave that up to the player to discover, to experience for themselves. Because I think that not knowing what you're getting when you go into the game gives a better experience to the player.

Moon's very funny and your other games are very funny. And I think humor is very difficult in video games sometimes, because at times games try very hard to be funny and it comes off as disingenuous. But I don't know, I'm curious how you approach making a game that is cheeky and silly and will make the player laugh? And especially when you have to then localize it because localizing humor is a whole different challenge in and of itself.

Kimura: So, it's a difficult one to answer actually. So I'm not necessarily, when I make games, I'm not looking to manipulate how the player's feeling. I'm not necessarily looking to make them laugh because some of the humor, it will make some people laugh, but for other people it might make them feel almost fear. And then I might make a scene that makes some people feel, "Oh, that's so sad," but other people would think, "That's cruel and horrible." You played the opening, right?

Yeah.

Kimura: So it opens with this: The player meets this guy and basically he takes him away somewhere and then the player gets sucked into this game world. It's kind of funny, but at the same time it's also kind of foreboding and the player's getting a sense of anticipation but also, "Look, what is happening here?" And that's what I'm going for, trying to just grasp the player and really draw their interest. And I think that's common to all my games. I'm not necessarily going for a certain feeling every time, just mixing things up.

So I get to thinking about what's good, bad, ******, white, good versus evil, is there even a clear split? And I think a lot of it comes from the experiences I had and the adults I met when I was a kid and how I interpreted those experiences, those meetings. And so my games, they're based in fantasy worlds, but there's definitely a certain element of my past experiences in them as well. I don’t know quite what those are? I don't know because it's all mixed up inside, but I'm sure some of it is in there. And that's especially true of Stray Children.

This is a really, really personal game for you, then?

Kimura: Yeah. Yeah, it's personal, but it's also a piece of entertainment. So it is a product at the same time as being a piece of art, I guess.

What am I not asking you about that you wish journalists would ask you?

Kimura: Apart from what type of game is this?

Haha, yes.

Kimura: I don't know, to be honest. And the reason is, when I was at Marvelous Entertainment and I was a producer, if you asked me about this or if you asked me about the game, I would have a prepared answer. I could tell you what the sales points were from a marketing perspective, but I've been working on Stray Children for three years now and I can't say specific points that I like because I like it all so much. When you asked me that question earlier, I couldn't answer straight away, it's because, A, I haven't been asked but also, B, I don't have that clear answer anymore in my head. Not at all. But if you've got any questions, I'm an open book right now for answers.

I like prompting people I interview like this at the end because sometimes creators have something that's in their head that is preoccupying them or that they're very excited about or that they think about all the time, but it's not always something that's been shown or announced or obvious for someone to ask about. So it's okay if you don't have an answer, but I like asking just in case.

Kimura: Actually, yes, having answered that, now I think I realize what I wanted to say. When we live our lives, there's oftentimes when we want to clarify what is right and what is wrong, have everything ****** and white. But recently, especially recently, I've been thinking that maybe that's not a good idea, and to have things gray, have that lack of clarity, a lack of a clear dividing line between those two things is a good idea. And I've been trying to, in various ways, have that element part of the game. And I know I play games, I've been making for a long time, I know what the player expects what a normal game should be, the user-friendly experience. Maybe there should be a warning at the beginning, but I should say sorry, just that this game isn't that way and it is my intent to do that as well.

A lot of video games over the years have tried to explore morality and as you say, in very ****** and white terms, where if you make certain decisions, you get a good ending and certain decisions you get a bad ending, and that's how it works. And even Undertale and Moon really worked that way, though I thought Moon's was…well, I got it wrong the first time. But I think now, especially in this oddball game space, there's a hunger to explore that a little more deeply and with more nuance. I'm experiencing that right now playing Deltarune, where I think the right and the wrong is a little less clear.

Kimura: It's pretty refreshing to speak about this. It's there, but I haven't really vocalized these things. I've been making this game for a long time, like three years, so every day it's like my life's energy is being sucked into this thing that I'm making. So at the end of every day I'm really just wiped out. And like you say, it is an odd game, so I need to be able to express in the marketing message from now... When we're going to release the English version, I need to be able to tell people all about it, but I just don't have the energy. I'm like, "This is a bit of a problem."

So up until now, with all the games we've done at Onion Games, once I've finished the game, I shift gears into this marketing mode, but this time I just haven't been able to, so it's a completely new experience.

Well, I imagine the smaller the game, the more personal it is to the people making it. And I imagine it's very challenging to have to sell what amounts to the contents of your heart.

Kimura: I've got really mixed feelings about it and it's kind of the same feeling about all of my games in some ways, and I think people who like my games would like this, and those that don't, won't. But this time around, the biggest difference is probably... Because the game was on Nintendo Direct, albeit in Japan, a lot more people probably know about it, than past games. So I think probably a lot more people will buy it, but I've been thinking about how some people think of games as a product and when you sell them, the more money you make the better. But I've recently been thinking about Stray Children that my strongest hope is that the people who buy it and play it will really love it. And if that's only a few people, then whatever. I really want it to reach the people that it should reach and the other people, if it doesn't reach them, then-

It is really a complex series of a mix of emotions, but to repeat what I said, I think that having it reach the people who will like it, will really resonate with, that's what I'm really looking for I think.

Post-Japan release, we've been polishing like crazy and everything is much improved, but at the same time I also realized that however much we were improve it, I can't please all of the people all the time. It's only ever going to please the people it's going to please.

[Translator pauses here and says, "I don't know how to translate this. Please do your best to make it into a comprehensive whole."] I haven't spoken to... I wouldn't say anybody, or that I haven't spoken to the media, but I'm half-feeling like when you get a bit tipsy and you start- So it's probably not your typical article that you'd write.

Well, I think you're better at selling your game than you think you are.

I turned off the recorder here, but I wanted to anecdotally include one last part of our conversation that occurred before Kimura sent me off with what turned out to be an excellent lunch recommendation, and has stuck with me since. As we were wrapping up, we got into a discussion about how overwhelming and oppressing the world feels nowadays, especially if you’re online or tuned into the news.

Kimura shared that in response to this feeling, he tries to focus on small joys. For instance, he says he’s recently discovered at his local convenience store a little apple pie, that only costs a couple hundred yen (a dollar, maybe almost two in USD). While the apple pie is meant for one, he’s figured out a specific way he likes to slice the pie into several pieces, and then he puts just one piece in the oven at home before he eats it so that the edges become golden and crispy.

In this way, he makes this very small joy last longer, and it tastes even better. That, he says, is how he’s trying to live his life right now.

Rebekah Valentine is a senior reporter for IGN. Got a story tip? Send it to [email protected].

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