The best things come in twos, and no better anime proves that than MARRIAGETOXIN! Gero, an assassin, and Kinosaki, his plucky, cross-dressing marriage swindler & counselor, find themselves in constant danger as Gero desperately seeks a marriage partner in hopes of saving his lesbian sister from an arranged marriage. Who knew marriage hunting could be so dangerous? 

At Anime Expo 2026, Anime Trending sat down for a series of interviews to discuss the show’s chemistry and action. First, we spoke with voice actors Haruki Ishiya (Gero) and Shion Wakayama (Kinosaki). Then, we spoke with director Motonobu Hori and producer Tatsuya Saito, who shared their thoughts on what makes this adaptation special to them.

This interview has been edited for clarity.

Searching for the Perfect Match with Voice Actors Haruki Ishiya and Shion Wakayama

Fans adore Kinosaki and Gero’s relationship, and it’s one of the most important elements of the story. Ishiya-san, as the voice behind Gero, how do you think Gero feels about Kinosaki?

Haruki Ishiya and Shion Wakayama

Haruki Ishiya: From my perspective, Gero considers Kinosaki first and foremost as the marriage-hunting consultant. But in addition to that, Gero also sees Kinosaki as a friend and a war buddy. Regardless of gender and how that might impact their relationship, I feel a heavy trust between those two.

As the voice behind Kinosaki, how do you think Kinosaki feels about Gero?

Shion Wakayama: Although Kinosaki and Gero are in a new relationship as new friends, it has become a relationship where Kinosaki would never want to break Gero’s trust. Ultimately, Kinosaki wants Gero to be happy.

Haruki Ishiya: It’s a mutual feeling for both of them. They both want each other to be happy and would do whatever is needed.

In the first episode, there’s a short scene where Gero sees Kinosaki with his latest swindling target and accidentally walks into a pole. People often wonder what Gero was thinking in that moment. What did you think was going on in your character’s head during that scene?

Haruki Ishiya: Since Gero wants to live a normal life, my interpretation of the scene when he was watching Kinosaki swindling without realizing what Kinosaki was doing is that he’s looking at something he can’t grasp currently. It’s almost like doomscrolling on a cell phone or watching a movie. That’s why I believe the logo of the anime’s title, MARRIAGETOXIN, shows up in the anime after that scene. It resembled the beginning of a movie in the way Gero was watching a movie in front of him.

©Joumyaku・Mizuki Yoda/SHUEISHA, MARRIAGETOXIN Project

Kinosaki seems relatively unfazed by all the dangers going around them after associating with Gero. In fact, they even show protective behavior toward Gero in the last Beast Master Arc. Why do you think that is?

Shion Wakayama: I think there are a lot of factors to Kinosaki and how they react to their surroundings. In the “Beast Master Arc” with Arashiyama as the opponent, a bunch of thoughts are going through Kinosaki’s mind. They’re thinking, “I’m worried if I can find Gero the right partner. I’m worried about Arashiyama as an opponent who’s facing off against Gero right now, and if Gero can handle him properly, but I’m also worried about my life, too. I’m worried because I won’t have the skills to deal with this. I don’t think Gero will let me down and endanger me, but I also don’t want to be a burden to Gero.” More than anything, Kinosaki wants to help Gero and be there so Gero doesn’t accidentally sabotage himself.

Outside of Kinosaki, which character’s relationship is your favorite with Gero, and why?

Haruki Ishiya: The character’s relationship I like personally with Gero is with Shizuku Ushio. She is an enemy, but she has great skills, and there’s mutual respect between her and Gero for their respective skills. Although there’s a business-type relationship, they also go through an enemies-to-friends arc, which is a pretty common arc found in shonen series. On top of all that, I really like the juxtaposition of Ushio’s personality of being cute while trying to hold onto a business-like persona.

Shion Wakayama: For me personally, I’m going to mention a character aside from Gero and marriage candidates, because I feel like if I say it, it’s going to be — you know. Don’t want to say anything’s certain! The reason why I like

©静脈・依田瑞稀／集英社・マリッジトキシン製作委員会

Gero’s relationship with Toshihiro is because I feel like he is also in the same situation. They’re both users from a major assassin clan, but they have two completely different goals: one is marriage hunting and the other is seeking power. To have that kind of juxtaposition while coming from similar backgrounds, it’s inevitable for them to collide, but there’s also an inherent understanding for each other at the end of the day. That kind of relationship I really do enjoy, and even with what we’ve seen, Toshiro is coming back in the original manga.

Upon seeing your characters on screen, what was your first reaction to hearing your voice and seeing your character?

Haruki Ishiya: At first, I thought, “He’s moving! He’s really moving!” It felt like I was an anime novice watching anime for the first time! After initially recording, I do see bits and pieces of the anime, but it’s incomplete, like some colors would be missing. Upon seeing the first episode, I was really surprised. The tempo of the episode itself was tighter than I thought, and it felt like a better tempo to the feeling I got when recording. The first episode is super important — it’s when he forms a contract with Kinosaki. So most of the episodes had been recorded at that point, but upon seeing the first episode and their first scene together, there was a piece that really fit for me. 

Shion Wakayama: I had a very hard time embodying Kinosaki, so watching the first episode, I was extremely nervous, just worrying whether I did a good enough job. But then, after watching the episode, the skill in the anime’s editing and overall production was just so masterful that it made Kinosaki really cute no matter what. So, although my skill might not have been there, the anime really just fleshed Kinosaki out. 

Wakayama-san, I disagree. I think your skill is absolutely there. 

Shion Wakayama: Oh, thank you so much! 

Haruki Ishiya: Throughout everything, just exhaustively, Kinosaki was always, always so cute!

©Joumyaku・Mizuki Yoda/SHUEISHA, MARRIAGETOXIN Project

Of the many scenes Kinosaki and Gero have with each other, which scene was your favorite to record and why?

Shion Wakayama: Favorite? But there are so many I like!

Haruki Ishiya: How could we just choose one? It’s like, should I answer with multiple favorite scenes? Or maybe the general theme of their scenes that I like the most?

Shion Wakayama: Oh, I do think I have a favorite! So in the scene where the aunt is speaking to Shiori at the company, Gero senses how the family reconciliation is proceeding well and preemptively leaves to not ruin it. Kinosaki praises him for that. I thought it was really cute that he was carrying Kinosaki, and Kinosaki was petting Gero’s head. I felt like the whole relationship really reveals itself there, and that’s why it’s my favorite. 

Haruki Ishiya: For me, rather than a single scene, it’s a theme. The thousands of times things don’t go well for Gero in his marriage hunting, and he really messes up to the point where he shouldn’t have, Kinosaki would pick him up. Kinosaki would tell him, “You can do it!” To me, personally, I felt motivated as well! So I really enjoyed those scenes. If I listen to them, I feel like I, too, can do more. It’s like having a Kinosaki personal recording for motivation. Actually, I could use one.

Shion Wakayama and Haruki Ishiya

Did either of you two run into challenges when recording, and if so, what was the challenge, and how did you get around it?

Shion Wakayama: Eh? Did Ishiya-san have a hard time at all?

Haruki Ishiya: No, I definitely did!

Shion Wakayama: Really?!

Haruki Ishiya: Really! As the main character, I understood the assignment was to be a character who needs to be rooted for. Also, as the main character, I understand that Gero is the core, and it needs to be a strong performance. I don’t have much experience playing a battle character, so I was wondering what to do with the battle scenes. He had a lot of battle scenes, so I was worried. There’s this balance in the battle scenes — he can’t get too emotional, because Gero’s character is also cool as well, but he is passionate. Finding that perfect balance was something that I really had fun with. There was a gap to master.

Shion Wakayama: Voicing Kinosaki was harder than I thought. They’re a unique character because they have a lot of perspectives, whether they’re a man or a woman. So I had a hard time grasping it and finding those multiple perspectives from within and getting that out.

Now that MARRIAGETOXIN‘s first season has ended, what do you hope viewers enjoyed the most from the series?

Shion Wakayama: I think it would be great if you could enjoy it while also enjoying the fun of hanging out with your real-life buddy. I think this buddy relationship between Gero and Kinosaki is what a lot of people liked! But also the marriage-hunt aspect — that’s something that I really hope people will enjoy. 

Haruki Ishiya: If you watch Season 1, you can probably tell there are lots of moments where missions fail or succeed, but at the end of the day, the characters keep trying. They’re facing life with a very positive attitude, even when they fail the first time. As any human watching the series, I hope everyone who watches can get inspired to pick up and try new things like what Gero and Kinosaki are doing together. And in Season 2, there are going to be even more funny scenes that could be especially enjoyed watching in a big group. So watch with a group of friends and share your comments while watching those funny episodes!

Behind the Scenes of Bringing MARRIAGETOXIN to Life with Director Motonobu Hori and Producer Tatsuya Saito

Motonobu Hori and Tatsuya Saito

How was the decision to turn MARRIAGETOXIN into an anime made?

Tatsuya Saito: I’m someone who’s known for my work in action series, such as My Hero Academia and Mob Psycho 100, but there are areas where I don’t have such traditional proficiency, for example, in love comedies or anything more romantic. That’s something I wanted to expand on, and my bosses knew about that. It was in that context, in my boss’s communication with Bandai Namco, that I was chosen.

Gero and Kinosaki are the two main protagonists of MARRIAGETOXIN, making their relationship central to the story. How would you describe their relationship and how they feel toward each other?

Motonobu Hori: Hmmm, this is a difficult question. Of course, we can say clearly they trust each other very much as partners, but I don’t think it’s… I think it’s better for me not to make a particular diagnostic comment on the relationship and leave that up to the viewers’ interpretation. I’m not the original creator, but I am part of the official team now associated with the work, and I think officially that’s the position we would want to take — that we would leave that up to the viewers.

Creatives often describe that every project, no matter how much experience they’ve had, is different. What has made MARRIAGETOXIN different compared to other anime projects you’ve worked on?

Tatsuya Saito: When it comes to characters, we really owe a lot to the amazing work of Kohei Tokuoka. And in contributing to the creation of the character designs, I needed to think, “How do I show Kinosaki in both a charming way, but also in a beautiful way? Both cute and handsome?” Those were the things I needed to think about and what I put into the project. 

©静脈・依田瑞稀／集英社・マリッジトキシン製作委員会

Motonobu Hori: To add to Saito-san’s answer, like he mentioned earlier, he hadn’t really done a romance anime before. For me, that felt very fresh, and what I really focused on when I was working on this piece was the way I felt, like MARRIAGETOXIN is emblematic of the era Japan is in now, the Reiwa era. This is a very Japanese way of explaining it, but we’re currently in the seventh — no, actually the eighth year of Reiwa — and this story has really made me feel its youthfulness. Let me explain what I mean by that. When I was growing up, I read battle action manga, or shonen manga, and this piece has a set of values that’s very different from what I grew up experiencing and watching. So even though it’s a battle action manga, it’s incredibly sensitive. There’s an emphasis on not incurring pain to others, and of course, this is something that’s in the original manga as well. I really felt a shift in values and saw how it was reflected in the anime.

We just interviewed Ishiya-san and Wakayama-san earlier. What about their auditions made you decide they were the right fit for the main characters?

Motonobu Hori: We had several candidates in mind, but one thing that was important for us wasn’t just each individual candidate’s voice. It was the chemistry of two different voices: would they pair well together? When it comes to Wakayama-san, I think her natural, normal voice is just so perfect for Kinosaki, and her talent in performing was really evident to us. I also think the fact that [since] we have a character whose gender is not clear, Wakayama’s voice is quite perfect for that. 

So in the case of Gero’s voice by Ishiya, we were looking for three particular things: the strength of the character in the voice, a certain kind of innocence in the voice, and finally, because Gero’s upbringing is so unique, he doesn’t have the common sense you’d expect. His ability to convey this strange combination was also important for us.

From left to right: Haruki Ishiya, Shion Wakayama, and Motonobu Hori

There’s one specific scene that went viral online for audiences in the West — in Episode 2, Gero uses poison and makes his target believe his hand got chopped off. Instead of blood, however, a rainbow of colors explodes from his arm. What was the thought process behind that specific moment?

Tatsuya Saito: Personally, I’m very glad this scene has drawn so much attention, but I think my answer is very close to what I answered for question two. If I were to give you a more surface-level response, let’s simply say I was trying to match the color palette to the overall expression of the manga itself. Of course, there’s much, much more than that in this particular scene, but I’ll leave the interpretation to the viewers.

What’s something in the anime you think viewers might miss that you would want them to pay attention to?

Tatsuya Saito: Both of us really think the music, and particularly the soundtrack, done by Taisei Iwasaki and Yuma Yamaguchi, the two amazing composers, is incredible. Of course, the audience will probably notice the songs associated with particularly happy or tragic scenes, but they should pay attention overall to the incredible composition of the piece. 

Motonobu Hori: So there’s another place I think I wish audiences would pay attention to. That’s the opening scene where we have a cross-cut back and forth between Kinosaki and Gero as they’re getting ready to go out. In Gero’s case, it’s set in his room, but in Kinosaki’s case, they don’t have a particular room — they’re always in different business hotels. If people could pay attention to that, I think you’d really get a nice point.

Now that MARRIAGETOXIN’s first season has ended, what do you hope viewers enjoyed the most from the series?

Motonobu Hori: The most amazing part of this series for me is the characters. Individually, they’re all created to be so likable — I hope the audience will love and appreciate them for who they are.. In Season 2, some of the characters remain, but there are also new characters, and I personally think the character development is even better in Season 2 than in Season 1. We’ve improved upon it, and I hope viewers will appreciate that too.

Tatsuya Saito: I’d be very happy if the audience comes to really appreciate Gero’s development as a character. If they’ve done so, I feel like it’s been a successful season, and that’s something that’s going to continue in the next season.

MARRIAGETOXIN Season 2 has been officially confirmed for January 2027. Season 1 is available to stream on Crunchyroll.