Sekai Oni is a strange sort of manga – imperfect and yet it fits with itself like a puzzle. No aspect of it holds it back; rather, it all holds together. I'm not sure if I can even supply any specific criticisms. It is what it is, and achieves what it intends to be. It's like a functioning grandfather clock – the gears, the pieces of machinery inside, might be flawed, but they all successfully and invisibly cooperate to bring you the end result. Is that an end result worth getting? I think so, but even if I know not what flaws it has, I don't love it completely.

I'm tentatively calling it an 8/10. I'll go into that later.

Story:

Sekai Oni is about a fucked up girl with a fucked up life who gets summoned along with several more fucked up people to defeat the World Devils that are going to destroy everything. I don't really consider it a spoiler to tell you what the manga itself tells you in its first few chapters; there's a great deal more to it anyway. Many surprises are in store, some of which I absolutely loved.

I would note that is not for the faint of heart. Trigger warnings would be abundant for those who believe in trigger warnings. It's not the most fucked up manga out there, but I'd be careful reading it in a public library.

Like its main characters, you'll be thrust into an unfamiliar situation where so much is going on that you can't understand. The manga does a good job of steadily resolving some mysteries while introducing new ones. Unfortunately, it runs into the issue that something mysterious is almost always going to be more interesting than something definite. I was somewhat disappointed by a few of the key pieces of the setting once I actually learned about them. Far from the worst, but not as intriguing as what you imagine beforehand. Alright, but not great. This brings down the quality of the second half.

And that's one of the few definite complaints I can even think of about this series.

A great deal of Sekai Oni is made up of fights, and they're good ones. I feel that a common metric for fights, these days, is how strategic they are. How many unusual powers interact in creative ways. This isn't one of those series, but that doesn't mean the fights are bland. There's a lot of powerful emotions in many of them, and some very meaningful decisions.

I will point out that these definitely aren't your typical battle shonen-type fights, of shouting, friendship and the like. No, Sekai Oni's fights are intense, a little gritty, and while fantastical, definitely very adult. There were only a few fights I loved, but all of them were at least good.

Overall, the story is a very interesting, unique fantasy, perhaps molded out of generic parts but built into something greater. Most of all, I'd call it unexpected. The overall tone is far on the darker side, and it definitely doesn't pull punches. The story is the primary reason I find it hard to criticize this manga. It's trying to be something, and it succeeds. The end result is great, and that's all there really is to it. I give the story an 8/10.

Art:

Sekai Oni's art is pretty good, but oftentimes rough or messy. The style itself is quirky and unkempt, which aids the freaky, messed up tone of the story. But oftentimes a character will just look poorly drawn, in a way that doesn't seem intended or important. Just rough.

The character designs are good and distinctive. That applies to the main characters, but to a larger extent to the monsters that they fight. There's a consistency and yet strangeness to their forms, almost like toys warped into something eldritch. When you see them, you don't just see interesting monsters, but an interesting category of monsters.

Admittedly, the backgrounds in Sekai Oni can be somewhat sparse, though at moments where it makes sense in the story. I wouldn't say the minimalistic style harms it during those parts.

The paneling is natural and easy to follow. Little of the series is visually beautiful, but it does the job, and looks great at a few impactful moments. I give the art a 7/10.

Characters:

The characters are one of Sekai Oni's strongest aspects. At least at first. I'm hesitant to say this, as it's nice to only gradually realize it as it goes on, but most of the characters you'll see in it are very fucked up people. Specifics would be spoilers big enough that I won't tell you. Most of them have various issues, and those issues are real. They reflect realities that people go through in real life. The manga deals with them somewhat tastefully yet doesn't pull punches in showing how awful they are.

And in a strange way, you learn to love the characters both in spite of and for their flaws.

The main character, Azuma, is definitely one of the most fucked up, and you can't even blame her given what her life has been like. It's not necessarily in absurdity, but in sheer scale of her personal issues and what they drive her to, that she is relatively unique among the cast. There's a moment when something about her character coincides with a certain story revelation, that turns into a satisfying twist, that made me shocked and yet grinning at how of course that would happen.

I don't know how to say this, but unfortunately, the characters aren't quite as interesting in the second half. I can't quantify or qualify this, but their growth and development grabbed me a little less than before. Perhaps it's just the direction Azuma then went in – I wouldn't say I disliked it, but I'm just not sure about it. She, and most of the cast, has strong character development, but perhaps I didn't fully buy a few aspects of hers.

Most of the characters were at least pretty good, and a few were excellent. I give the characters a 7/10.

Enjoyment:

This is perhaps Sekai Oni's strongest suit. These days, I've found it hard to get into most manga, and tend to always be forcing myself through even if I like a series. Sekai Oni was a wonderful exception that kept me on the edge of my seat and unable to stop until I made it to the end. It took a little while to get going – this won't grab within the first few chapters. But it definitely should be within a dozen or two. Even through the marginally inferior second half, I couldn't get myself to stop.

It's gripping and intense, and at many parts it is what the characters are going through that kept me hooked. There were plenty of powerful moments that left a big impact on me.

I give Sekai Oni's enjoyment a 9/10.

Overall:

I'm having a very hard time judging. If you read through this review, you might think I've summed up its good points and bad points. But the fact is, 90% of how I feel reflects what I said at the top: Sekai Oni fits together and accomplishes its goal, and it's hard to put your finger on just what it did right or wrong.

Is it a 10/10 manga? I'm afraid not. I've read series I consider 10/10s, and this definitely isn't as good. And yet, where were its mistakes? I don't know.

It feels strange to say that a manga can be exactly what it is supposed to be, and yet still only come out as a 7/10 or 8/10. Perhaps the creator's original ambition simply wasn't so lofty.

I hope you'll read the series and understand what I'm trying to say here. You might agree, or you might see more clearly why it is imperfect. If you do see, I hope you'll tell me, because I'd love to understand it myself.

But I also hope you'll read the series simply because it's very good and you'll enjoy the experience. And it's because I feel that sentiment that I'll give it an 8/10.