Cliche reigns supreme here, to this story's detriment. If you've been a manga/anime patron for a little while, you already know all the notes it'll hit. Episodic structure. Cutesy normal girl who gets helped by alternately cool and goofy protagonist and gloms onto him like a puppy for the rest of the storyline.
Protagonist has big tough scary out-of-control supernatural dark side that's a risk to him and those around him. Of course, he also had some past love interest who died and hence he won't put anyone else at risk - or so he claims, but does so anyway.
Lots of ambivalent fussing about the safety of aforementioned normal hench-girl, who of course has no qualms about endangering her own safety so she can fill out her checklist of stock character traits. The list goes on. If you haven't read something like it already, you will before long.
Cliche can be okay, but it doesn't have a lot of strong notes to offset it. The art style is kind of chunky and bland without a lot of detail (though the action is nice and clean and easy to follow, which is a plus). There's some competent spooky imagery early in the story, with a little atmosphere. It doesn't really last past roughly the first volume, and any time the atmosphere does build up, the emphasis on action undermines it fast. Consequently, it doesn't really work as a horror story OR a detective story, but just falls under a sort of bland shounen umbrella. The urban legend theme is cool and makes for a good structure, but it's employed in a haphazard, sloppy, and poorly explained way that introduces a lot of plot holes, some of which get answers that only raise more questions. The characters themselves are poorly defined, and don't really have cleanly defined personalities beyond a few inconsistently-utilized little traits that get stuck to them like badges and often forgotten. The story itself has so little throughline that the final plot arc just sort of smashes into it like a freight train out of nowhere, with no real prelude other than establishing a certain character involved exists. Nothing about them, or what they want, of course. The entirety of the setup for the final act is, "Hey, this character happens to exist!"
That's not just the setup, though. That's also all the explanation the character ever receives. When the protagonist asks just exactly who they're supposed to be, he's asking a question the author forgot to answer.
Overall, it's harmless and kind of cute from time to time, and offers a rare few spooks, but it's hampered by paint-by-numbers story and characterization, without doing anything to mix up the cliches it leans on.