The Spring 2026 Anime Preview Guide

Kill Blue

Grizzled forty-year-old hitman Juzo Ogami has been living in the shadows his entire life. He tried the wife-and-family thing, but it ended in (amicable) divorce, and now he's back to just living for the job. Only his most recent job lands him in some unusual trouble – during an assignment, he accidentally unleashes a genetically-modified wasp, and when it stings him, he's returned to his thirteen-year-old body. The only way to figure out how to reverse things is to get cozy with the daughter of the pharmaceutical group that developed the wasp, so now Juzo has to take on a dangerous new job: attending middle school.

Kill Blue is based on the manga series by Tadatoshi Fujimaki. The anime series is streaming on Crunchyroll, Netflix, Amazon Prime Video, Rakuten Viki, Plex, and REMOW's It's Anime YouTube channel on Saturdays.

If you watch just one of the two shows about adult men regressing to teens, I recommend this one. Kill Blue's premise is perhaps more insane, but it also somehow manages to strain credulity less than Haibara's Teenage New Game+. Juzo, the protagonist, isn't haunted by dreams of redoing an earlier period in his life; he's largely doing just fine as an adult…or at least, just fine enough. Yes, he's divorced and doesn't seem to see his daughter often (or at least, that's my interpretation of him not panicking about her after his regression), but he's content enough with his job as an assassin. He's not looking at being turned back into a thirteen-year-old as a major win or second chance.

That's what makes my favorite part of this episode so good. Juzo's not enthusiastic about finally going to middle school (he dropped out before that point before, compulsory education be damned), so he's completely caught off guard by the fact that he freaking loves learning. Negative numbers are a revelation to him; social studies gives him a stronger connection to the world around him. He wishes he had more homework, because he finishes what he's given too quickly. He's gone from assassin to study-obsessed in record time, and I love that. He's basically a dream student, even if his classmates think he's weird, if not worse. Part of what makes it work is his lack of enthusiasm for being regressed. His love of learning is a pleasant surprise rather than a deliberate wish of his adult self. He's not trying to redo anything; he's just found something he never expected to.

Of course, his old assassin skills still come in handy when a pervert known as Panda Mask shows up at school. He applies an adult lens to the situation, but not the one he's been trained to use: he fights back because the girls Panda Mask is targeting are the same age as his daughter. It's not his problem; they haven't been nice to him, but when it matters, he puts on his adult pants and helps them because that's what he'd want someone to do for his kid. It says more about him than almost anything else in the episode.

It also reveals that he's been carrying his gun around in his schoolbag. I have feelings about that that don't necessarily belong in a silly story about an age-regressed assassin learning he loves math.

Kill Blue's first episode is fun. It sets up an ongoing plot about the pharmaceutical company that apparently developed the age-regressing wasp Juzo was stung by, establishes Juzo as a character, and hopefully doesn't set up anything between him and Noren, the daughter of the people who developed the wasp. It's worth checking out.

We've seen all of the tropes being exploited in Kill Blue plenty of times before, which means that the show's success more-or-less rests entirely on how entertaining it can make this particular concoction of familiar archetypes and story beats. Juzo Ogami is one of this preternaturally talented killers that also happens to be a big softie who only murders truly bad people. He's emotionally stunted and isolated, sure, but he's no sociopath, which the show makes clear when we learn that he has a wife and a kid, even though he was just never able to truly make it work. Even the show's biggest Weird Sci-Fi Gimmick - a genetically engineered bee transforms Juzo into a middle-schooler which forces him to go undercover amongst a generation of Zoomers - is old hat so far as anime is concerned. Basically, Kill Blue asks, “What if Detective Conan was, like, good at sniping people and stuff?”

When I finished this premiere, I immediately turned to my wife and said, “This is a Lunchbag Lay's anime if ever I saw one.” For anyone who may not be familiar with the cultural staples of cheap school lunch accouterments, Lay's Potato Chips sells these little 1 oz. bags of their classic-style potato chips that are essentially a guaranteed inclusion for any field trip luncheon or midday snack on the playground. They're cheap, salty, and utterly devoid of meaningful nutrients save for basic calories, but that's what makes them tasty. That said, I don't know many folks who would kill to trade for a Lay's during recess, nor do I imagine many savored childhood memories revolve around shoving greasy handfuls of crispy potato shards down one's gullet.

The point is, while it is slickly produced and moderately entertaining, everything about Kill Blue makes the experience into the anime equivalent of scarfing down a Lunchbag Lay's to settle down your stomach until the real lunch arrives. Its hero, Juzo, is only vaguely compelling as a fish out of water who must acclimate to the wondrous novelty of attending middle school while also figuring out how to deal with all this newfangled technology and lingo that kids these days are obsessed with. A couple of jokes or heroic moments may have made me smile enough to acknowledge that the story was, in fact, functional enough to be engaging, but I can't say that I genuinely cared about anything that happened in between the opening and closing credits.

There are a couple of moments of decent action sprinkled throughout, but nothing that would make this a truly memorable action-adventure anime. Kill Blue, so far, feels more like a broad comedy that is only intermittently funny and just so happens to occasionally feature a decent fight sequence. At least the English dub on Amazon Prime is fairly good unlike the recent abomination of Fist of the North Star's adaptation. It helps to sell some of the goofier moments, and I'd recommend it to anyone who just wants a half-hour or so of mindless entertainment.

Maybe it's just a matter of my ageing out of the target demographic. Despite the fact of our hero being a middle-aged man trapped in a tweenage body, this is clearly a series meant to appeal to the actual middle-schoolers in the audience. I can imagine a room full of thirteen-year-olds getting a kick out of the silly visuals and ridiculous assassination story elements. For me, though, this is the sort of junk food that my doctor keeps telling me I need to strictly limit for the sake of my diet, and there are plenty of more appetizing picks to choose from this season.

At some point during the episode, I realized: Kill Blue is weird. To be clear, I mean that in a good way! Weird is good! Weird sets you apart from all the other bland-ass shonen action series! I don't know if Kill Blue will end up having any significant structural differences from other lesser shows in the the genre, but it did make it so I actually enjoyed the first episode.

Like every other anime assassin, Juzo won't take just any job; he only kills the worst of the worst. The bad seeds. The villains beyond redemption. Killing is the only thing he's ever known, and he lacks even a middle school education. His life is utterly empty of anything else, but at least he has a moral code. Blah blah blah, etc., etc. It's so cliche that I almost just called him Gero, the socially maladjusted assassin who wasn't allowed to attend school at the center of the far superior MARRIAGETOXIN. I found myself thinking of Yakuza Fiancé, which made no excuses for its characters, no sense of justice.

But then Gero – this is not a bit, I legitimately did that by accident – I mean, Juzo wakes up as a 13-year-old and heads to school. Does he, a 40-year-old divorced man who pays child support, start thinking of the girls around him like Haibara of Haibara's New Game+? Does he try to recapture his lost youth? No, he gets excited about the education he could never access. It's a deeply pure-hearted reaction, a reminder that education is a privilege that people have fought to access for generations, that many still have denied to them. I can't be sure if it will avoid the weird implications of a middle-aged man being surrounded by young teens, especially if it acknowledges his adolescent hormones the same way it does other aspects of his body changing, but his excitement over using a microscope was so adorable that I want to give it some grace.

On the other hand, I didn't love how the story saw fit to threaten his bullies with sexual menace. Yeah, sure, he saved them, but there was a sense of them deserving what they got if they ended up seeing a guy's dong against their will. A one-off jobber being a weird flasher in a panda mask and boxers who shows up at the school completely disconnected from the central conflict? That's fine! Juzo winning over a pair of girls who picked on him by saving them from a sex crime? That's not fine, even if the panda man's gleeful gyrations would have been hilarious in any other context.

Kill Blue is a perfectly acceptable shonen series that I can kind of recommend to fans of such material. It even gets an extra half-star for being based on a completed 13-volume manga, which is a perfectly sensible length for this sort of story.

“What if Detective Conan, but with an assassin instead of a detective?” I feel like that has to be the inspiration for this anime. Of course, it's not like this is the first anime where an assassin has been turned into a child. While it had an isekai twist, The World's Finest Assassin Gets Reincarnated in Another World as an Aristocrat had a similar base premise for one.

However, Kill Blue does manage to zig where similar stories have zagged. This is because this entire first episode is focused solely on Juzo, who he is, and his already established relationships. Basically, Juzo is a highly proficient killer. However, he is also one with an ex-wife, daughter, and little to no formal education.

The latter bit is the real highlight of this first episode. Juzo was already an assassin the first time he was 12-years-old. There is no reason he couldn't continue doing his job this second time around as well. However, being forced into a normal middle school as part of a job, he discovers that he actually loves learning and gives his all for it.

I think this is something that any adult who has “gone back to school” can understand. Rather than when you were a kid and class was just getting in the way of doing fun things, as an adult, you're there because you want to learn. That shift in mindset changes everything. Class becomes a joy, and study isn't done just to pass a test but to actually learn.

All that said, I didn't really enjoy this first episode as much as I feel I should have. I wanted more with his ex-wife and wanted to know a bit more about his kid—and I'm kind of shocked that his daughter doesn't go to his school as that would make for a ton of potential story options. Likewise, none of the characters he met at school, even the bullies he saved, feel like anything more than background characters. The world in which the story is set just felt flat rather than dynamic. I hope that changes in future episodes but I'm on the fence as to whether I'll tune in and watch or not.