Murciélago is unapologetic trash; the main character is a serial killer and predatory lesbian, her sidekick-slash-implied “best for last” target is god's dumbest soldier, and the gory deaths go beyond shock value and wrap around to being bombastic comedy. All of this might sound like I'm about to tell you all the reasons not to read Murciélago , but these are all the reasons you should consider it; if anything, the series, which is now nearing 30 volumes and an upcoming anime adaptation, feels like a time capsule to 2010s manga, especially darker seinen series in the wake of Hellsing and earlier 00s shock and gore works.
Hellsing especially feels like it had some impact on Murciélago , as extremely lanky Kuroko is often depicted in the same angular, odd ways Alucard was, and their roles as monster-killers make for a fair comparison. Where Hellsing veered into supernatural schlock and over-the-top powers, Murciélago has more of an interest in exploitative action media: bodies explode and are cut, torn, and otherwise brutalized in all sorts of bombastic ways, cars literally hop rooftops and do the impossible, and supposedly normal humans in a world without supernatural powers do things that stretch most people's suspension of disbelief with action stories.
Kuroko is perhaps the biggest barrier to the work: she is either going to repel you with her unrepentant enjoyment of murder and her predatory lesbian stereotype that includes actual sexual harassment and, frankly, sexual assault (in the form of groping and other things; the sex she has is always implied to be consensual). As I mentioned above, she reminds me a lot of Alucard, but far more divisively; Kuroko is almost less interested in being human than Alucard was, and instead a beast on the government's leash for as long as it seems to interest her to be alive. She exudes a certain level of superhuman cool-factor that is almost as potentially repulsive as her characterization; there are numerous points in the first three volumes that defy belief and offer no explanation as to how she can do these things or what gives her such ability to kill, fight, and survive the way she does.
Kuroko's sidekick of sorts, Hinako, is similarly jarring. Introduced initially as a test of whether Kuroko can be trusted not to kill wantonly, her “job” in the manga is to drive Kuroko around when she isn't being one of the dumbest characters to ever grace fiction, really testing the boundary of a “childlike” mindset. The first volume features some odd juxtaposition where Hinako is, supposedly, a girl that Kuroko wants to sexually assault or conquer and then kill as her “final” kill, but that seems to fade out of the narrative as the story progresses. Kuroko instead, by the end of volume three, almost starts to resemble some bizarre daughter that Kuroko, a literal serial killer, is taking care of and will kill anyone who attempts to harm her.
All of that is to say that Murciélago exists in a sort of category that is pure trash, and it often feels great to read; it may be the epitome of junkfood style manga, as nothing here is good for anyone, nor does this work do anything to help promote the human spirit or experience, but boy, are some of the action scenes and fights just downright cool. If anything, these first three volumes are clumsy at getting into the groove; as mentioned, Kuroko becomes almost immediately flanderized, but making her a slightly more likable antiheroine improves the manga. Volume 1 especially spends a lot of time finding its voice, with volumes 2-3 taking the story through 2 arcs that set up the “monster of the week” style of challenges that let Kuroko kill terrible people for our amusement.
Perhaps the most divisive aspect of the work is Kuroko's sexuality, which I think depends a lot on what you're looking to get out of a character that is an open lesbian. Murciélago isn't trying to be a coming-out, coming-of-age, love story, or slice-of-life story featuring a queer protagonist; Kuroko is a lesbian primarily because the author, Yoshimurakana, says he likes yuri. I've referred to her as a “predatory” lesbian because, aside from the fact that she constantly flirts, gropes, and otherwise comes on to women, she also sort of fits a very Japanese style of lesbian that preys on other women, sort of in the homophobic vein that straight men tend to believe gay men will try to seduce them at the gym or something.
When I first read Murciélago over a decade ago, I had some very mixed, scandalized reactions to Kuroko. It felt like I was reading taboo adult pornography in between the action, but over time I've come to reconcile some of those feelings with a bit more fondness for the overall package. Yes, it was initially cool but shocking to see a lesbian protagonist who then turned out to be a schlock action monster, but as I've grown older I recognize that Kuroko is not meant to be an uplifting or revolutionary queer protagonist: she is the protagonist of a B-movie, and she rules.