According to the author's notes included at the end, this manga is actually the adaptation of a 2011 novel originally titled Invented Inference: Steel Idol Nanase, which has not, to my knowledge, even been licensed yet for an English release. (The "Steel Idol" in the title is a reference to the urban legend mentioned in the Synopsis.) The source novel was written by Kyou Shirodaira, who may be much better-known to anime and manga fans as the source novel writer for both Spiral and Blast of Tempest, and he is credited for the story for this manga version, too. According to his own account, though, manga-ka Chashiba Katase actually did most of the work and is responsible for any variations between the manga and novel. Shirodaira also mentions that the title given to the manga form is a bit deceptive, as it implies more of a sense of mystery and investigation than what the story actually has.

That's good to know, because what little there is for a mystery aspect in this volume is thin indeed. It instead looks much more like a tale about a duo strongly affiliated with yokai who go around dealing with yokai matters, although there are also late indications that a third person is going to be dragged along for the ride. Based on what is shown in these two lengthy chapters, there are three reasons for including Saki: to have a “normal” person to provide a reader viewpoint, to create a love triangle, and to give a police connection that will doubtless prove very useful in some of the cases.

How well that's actually going to work in the long run is another story. To be sure, Saki candidly mentions that Kuro is her “type” both physically and in terms of personality and she clearly deeply regrets breaking up with him (and why she did), so all of the impetus for a renewed romantic entanglement is there when she and Kuro eventually meet up again. The way it is being set up is every bit as awkward and forced as Kotoko's attempts to win over Kuro, though. And while the latter may be intentional – this is, after all, Kotoko's first effort at trying to seduce someone – the former isn't. The writing is going to need to smooth that aspect out for an effective love triangle to form.

The overall structure of this volume is also odd. Kotoko and Kuro are cast as the main protagonists, and the entirety of the first chapter is spent describing their situations and how they come to be a couple. Then there's a 2½ year time jump into the second chapter, which focuses entirely on Saki and doesn't have Kotoko appear until its late stages. (And Kuro doesn't appear at all.) So, in essence, what should be the two main characters entirely disappear for about a third of the first volume. The half that focuses on Kotoko and Kuro also takes its sweet time getting to the reveal about Kotoko missing both a leg and an eye, which initially gives the sense that she is just walking around with a cane as part of some inexplicable affectation. Essentially, the organization of what happens suggests that Katase is considerably less experienced than Shirodaira when it comes to putting the story together.

The characters come off fine, though. Kotoko may be doll-like cute and have a proper air about her, but she is anything but stereotypical. She is aggressive towards Kuro but not in the physically overbearing way typically seen of aggressive girls in anime and manga; her attempts to capture her romantic prey involve logically and verbally pressing him in such a way that he has no alternative but to accept her as his new girlfriend, as she leaves him no “outs” to refuse her. He's creepy because of how yokai react to him? She sees that as a plus! He's on the rebound? Just the opportunity she was looking for! And so forth. She's also quite cheeky, such as the curious way she uses to describe how painful something is when she meets Saki. Kuro, meanwhile, seems to want to be distant and standoffish but the women in his life just won't let him do that. He gives the definite sense of just giving up and going with the flow, which may be why both Kotoko and Saki picture a goat when they think of him. (It is a reference to calling Japanese men who seem to lack sex drive “herbivores.”) Saki could probably carry the series on her own with her mix of both toughness and sentimentality; I could envision her getting her own spin-off at some point if the franchise is a big hit. She and Kotoko should clash quite nicely. Many of the bit-part yokai are also amusing.

While the storytelling may be a bit rough, little is lacking in the artistic effort. Characters are cleanly-drawn and attractively-designed without being too stereotypical, and Katase has a good eye for posing Kotoko in particular. Yokai design is also suitably creative. The staging of a handful of action scenes is nothing special, with the framing adequately displaying what's going on but not evoking much thrill factor in the process. Background art is skimped on a lot but very solid when it is present.

Kodansha Comics releases this title in a format similar to a typical Yen Press release. Sound effects are unobtrusively translated in addition to the original on-panel text and the aforementioned two-page greeting from the author follows the second long chapter. Following it is a six page bonus short about a kappa who seeks to meet Kotoko and three pages of detailed translation notes.

Despite its early issues, In/Spectre does hold some promise, and the issues it has are ones that could conceivably be ironed out going forward. If this ever gets an anime adaption, though, then I hope that the director adapting it rethinks how to reorganize the content of these first couple of chapters.