It seems to have got relatively little fan attention, possibly because it aired its episodes out of order. The final episode isn't the finale, etc. That was probably off-putting for casual viewers. The original manga (by Coolkyoushinja and Johanne) gave us two main characters: Mikoto and Sally. The anime staff wanted to concentrate on just one of those, while furthermore the manga was still running and it wasn't obvious which part of it should be turned into the finale for a twelve-episode anime.
The director wanted to focus on Sally (the correct choice), even though the rest of his staff had been expecting to focus on Mikoto. In his opinion, the real start to Sally's story was when she met Frau, with her earlier meeting with Mikoto relegated to a flashback. If you want to watch in unscrambled order, though:
Manga-chronological order: 4, 1-2, 7, 11-12, 5-6, 3, 8, 10, 9
...with ep.9 coming both first and last because it's 99% flashback.
Oh, and even ep.9 doesn't end the story. You don't get closure and final answers, although you do get some satisfying disclosures and developments. I might buy the original manga next time I'm in Japan, partly because I like Coolkyoushinja (Miss Kobayashi's Dragon Maid
, Komori-san Can't Decline
and I Can't Understand What My Husband Is Saying) and partly because I want to see the rest of the story. What happens to Sumeragi? Why does Sally have Mikoto's peach-eye powers?
I like the story. It's a retelling of Momotarou, the Japanese folk tale about an oni-slaying small boy. (His name means "peach boy", c.f. the title.) Here, there appear to be multiple Momotarous. One is Mikoto, a pretty, ever-smiling but bloodthirsty sadistic killer. He kills vicious man-eating monsters, yes. He does good. He is, nonetheless, alarming. The other Momotarou is a princess called Sally who has oni-slaying superpowers for some unexplained reason, but hates discrimination (even against oni) and wants to encourage peaceful coexistence.
There are hundreds of SF/fantasy stories with fantastical racism. This one has more bite than usual, though, because oni are man-eaters to the bone. There are oni who marry humans, but then in an unguarded moment kill and eat their spouses. They'll hate themselves afterwards, but that won't bring back the dead. Sally's arguing for peaceful coexistence with creatures like that.
That's a strong basis, on top of which I like the cast. Sally's much more likeable than Mikoto, although the latter has some interesting developments later on and I'm definitely interested in seeing where that goes. Frau is the greatest. Frau is a rabbit-thing with a charmingly half-drawn face, an unbreakable sense of gratitude and some very odd abilities. Carrot has quite a character journey, being an oni and so essentially evil. Finally, the ordinary human Hawthorn is underpowered by the standards of Sally's party, but he doesn't let that stop him and he also provides a small amount of gender balance.
Also, Sumeragi is a bastard. After finishing ep.12, I immediately looked up the chronological watching order to see if I'd missed Sumeragi getting his just desserts in some earlier episode when I hadn't realised what I was watching. (I hadn't. Drat.)
This show is worth both watching and rewatching. (In a different order.) I particularly love Frau. For me, this one's a keeper.