It's easy to look at Rei Tōma's art and forget just how dark her stories can get. Both Dawn of the Arcana and The Water Dragon's Bride concealed dark plotlines beneath their otherwise fairly typical fantasy plots, and The King's Beast doesn't seem to be an exception to Toma's rule. Set in the same world as Dawn of the Arcana, the story follows Rangetsu, an Ajin (human with animal features like ears and tails, superior senses, and healing abilities) as she seeks revenge against the human(s) who killed her twin brother Sogetsu years ago. And if you thought things were bad for the Ajin in Dawn of the Arcana, prepare yourself for them to be treated even worse here in a different nation.

While Ajin were hardly prospering in the more European country where Toma's previous series was set, in this land Ajin are absolutely second-class citizens. Families are only allowed one child (excluding multiple births, which is how Rangetsu even has a brother), men and boys are conscripted into either the army or as bodyguards known as Beast-Servants, and women are forced into sex work when they're young and switch over to menial labor when they age out of that. Children are tested at about age eleven to see if they have any special powers (the one we see in the story is a magical skill, but nothing says that they're all magic-based), and Sogetsu, much to Rangetsu's horror, tests positive for them. Because of that he's shipped to the palace as a Beast-Servant, and shortly thereafter dies in service to the Fourth Prince.

To say that this changes Rangetsu's entire world would almost be an understatement. She's crushed by her brother's death, but that also ultimately becomes her salvation – at least from the fate she as a girl is destined for. It's worth noting that Toma doesn't shy away from the brutality of Rangetsu's existence as a female Ajin in this country: just before she's of age to be sent into sex work, a group of human boys harasses her about it, crudely propositioning her about her forthcoming “availability” and how their leader (who doesn't look more than twelve) is going to be first in line for her at the brothel. Shortly after that her mother actually brings her to the brothel, where she's to be initiated into her new job by being raped by the man who runs the place, making it clear that this is the usual process for girls like Rangetsu. But unlike those other girls, Rangetsu has a lot of anger simmering just beneath the surface, and she manages to escape, cut off her hair, and, masquerading as a boy, get enough training to become a phenomenal fighter – all so that she can be named Beast-Servant to the fourth prince who she believes killed her brother. What's particularly impressive about this sequence is that it's done almost entirely without words; Rangetsu has some narration, but for the most part it's a silent reel of horror, which makes it especially effective.

Although this does have a lot of unique elements to it, one piece of the story comes just as expected – the fourth prince, Tenyou, is in no way the person Rangetsu expects him to be. Since the story might be much shorter and less interesting if he was, it's hard to count that as a surprise or a spoiler, especially since we have to assume that a romantic subplot will also rear its head at some point in the next couple of volumes. Tenyou, as it turns out, hasn't had a Beast-Servant since Sogetsu, in part because we get the impression that he disapproves of the way humans treat Ajin, but also because he feels incredible guilt over the boy's death. He's actually just as keen to find Sogetsu's killer as Rangetsu is, and in fact attempted to before being told to knock it off by his father. But now that Rangetsu has been given to him and has expressed her determination, Tenyou has an excuse to pick his investigation back up, something else Rangetsu wasn't counting on. More than anything, Tenyou forces Rangetsu to rethink her prejudices even as the other princes and Tenyou's retainer Taihaku continue to reinforce what she knows about humans. It's an uncomfortable place for her to be, and the book does drop the ball somewhat in conveying that, keeping Rangetsu as angry and otherwise inscrutable as possible, which may be in service of how her relationship with Tenyou will eventually develop.

Toma's art is more polished here than in either of her previously released series (and it is interesting that she only started to get English translations when she shifted from school drama to fantasy), something easily noticeable by the included The Water Dragon's Bride epilogue. Unlike the Ajin who played main roles in Dawn of the Arcana, Rangetsu is a fox-based Ajin, which gives Toma a little more to work with in using her ears for expression, but also got her into a bit of trouble when, as she states in an author's note, she accidentally used someone's fox mask design before getting permission. (Rest assured that she now has it.) Rangetsu using a mask is in line with her disguise, however, and it is a neat design, so it's good that it can remain in the story.

It's always interesting to look at Viz's content warnings because they do sometimes slip something fun into them, such as Black Lagoon's or the inclusion of “This volume contains a grudge” in Skip Beat!. The King's Beast lets us know that the book contains “systemic oppression,” and while that may not be a content warning per se, it certainly does give us a good idea of what Rangetsu is really working against. It's a dark start, but it also is a good story, one where very few people are what they seem to be. The system of oppression is looking like it might be ripe for being shredded, and change clearly lurks just around the bend. I don't anticipate this being an easy series, but I'm willing to bet on it being a good one.