A fairly classic edgy "Victorian all-stars" detective action show that will instantly amaze you with its incredibly cool combat animation and strong atmosphere in the spirit of Black Butler or Princess Principal. If you like these types of shows inspired by The League of Extraordinary Gentlemen, then here you will find everything you could be looking for. Ranging from Victorian homoeroticism (FoYay between Shizuku and Carmilla is one of the best I've seen in an action show) to a full cast of 19th century memetic characters. Although the mention of Aleister Crowley among fictional characters made me laugh a little, yes.
I'm glad that three of our heroes were original, so the creator of the original novel did not have to change the biography of someone too much for this. But this does not mean that they work as self-inserts. Tsugaru, Shizuku and Aya play off each other quite well, both through verbal exchanges and detective and combat cooperation. Some of their quirks can be annoying, undeveloped (at least within the first season), or one-dimensional, but it still works, at least for me. What I'm confused about is the rather blatantly hypocritical act of one of the trio in the show's finale, which is quite difficult to explain even within the framework of mental gymnastics or edgy mentality. At some point, even the villain themself legally points this out, which is not something good.
Ultimately, we have a pretty good, high-quality example of its genre or aesthetic that can be recommended to anyone who enjoys the setting and/or incredibly animated character fights with superpowers that aren't just chaotic big explosions and destruction. As I said above, the ending will definitely raise your eyebrows more than once, but this is not the type of show where the mixed ending is ruined whole anime at once. Although it will definitely leave a bad aftertaste if you like to get immersed in the story. So, with a clear conscience, I give this show an 8 out of 10, but within the framework of mixed feelings, and not a full-fledged recommendation.