This relatively short manga—you can finish it in an evening—immediately stands out thanks to its unconventional protagonist, CGI-heavy backgrounds the author is known for, and some thriller/body horror elements that may and probably will disturb the squeamish.
So, is it actually good? I would say it's almost there. It's rather captivating, fast-paced, well-drawn, and can be touching at times, so I would give it a very soft recommendation. Could it have been great? Yes, definitely—but alas, it wasn't.
See, Hiroya Oku has this weird problem where he can come up with something promising... and then seemingly have no clue what to do with it. Because of this, there always comes a point in his stories where they start dragging their legs, so in order to counteract this he rushes the ending in a needlessly convoluted and/or ham-fisted fashion. Gantz was exactly the same in this regard, except it was also pulled in all sorts of weird directions first, leaving a lot of loose plot ends. Thankfully, this isn't the case with Inuyashiki, but this isn't to say what Inuyashiki does well it actually does better than Gantz. Because it really doesn't.
First off, the characters. The protagonist is, indeed, reasonably fleshed-out. We get to understand his living situation, his relationship with the family, and his outlook on life and his motivations very early on, so nothing he does afterwards feels out-of-character in any way. The supporting cast is very small and unfortunately doesn't quite receive the treatment they deserve, but at least they act believable enough for it not to bother me too much. More importantly, the author does a good job at letting the cast act out their personalities rather than dumping exposition via dialogues and narration. This is certainly a good thing and a mark of experience.
The main problem is with the character development in general, especially the antagonist. Without getting into the spoiler territory too much, let's admit from the beginning that he isn't entirely unrealistic—I could very well see his situation play out in real life and interact with his mental troubles the same way that would've led to similar events as described in the manga. Especially the classic downward spiral situations that go beyond Dostoyevsky's Sin and Punishment and get closer to, say, Breaking Bad in terms of bad things continually coming to worse in a domino effect. But while he gets a lot of screen time, we never get to truly understand his personality or motivations. The author decidedly detaches himself from the antagonist, as if afraid to explore him, even though for a simplistic good-versus-evil conflict like this having a strongly written antagonist is *everything*.
And I cannot stress the importance of a good antagonist enough. If you take any truly great villain from movies, books, manga, etc., they all have one thing in common: we can relate to their philosophical outlook and/or their motivation that put them on the path to destruction. It's only this way that the work can inspire us to think and ask ourselves whether we can avoid being twisted by our aspirations, whether we understand what makes us evil, and whether we can draw the line correctly and retain our humanity when we end up in a desperate situation. The aftertaste of a story, the lingering thoughts that occupy us long after we close the book and help us continually question, rethink, and ultimately flesh out and improve ourselves as persons is what a great story is truly about.
Instead, the way the story progresses in the middle, we get to see, almost in a slice-of-life fashion, how the good guy does the good things and the bad one does the bad things. Just to drive home the contrast between the two. In fact, the author seems to be obsessed with showing any such contrast to the audience as explicitly as possible to make absolutely sure everyone gets it. I mean, the protagonist's surname translates to something as silly as "dog house", and the antagonist's is "lion god" (and his first name is an homophone of "hero")... This kind of deliberate—if not desperate—attempt of subverting expectations lands dangerously close to self-parody, and it's not really a good thing.
Owing to this, the protagonist's personality traits quickly become stale, and as a reader I would've lost all investment in him if it wasn't for his interaction with other characters. And for the antagonist, there also comes a point where he noticeably crosses the point of no return, and it seems like there was nothing left to do with him other than keep upping the violence ante. You will surely notice this point as well and upon finishing the manga it won't be hard for you to realize that what comes afterwards is an incredibly convenient way to wrap up the story without it completely losing the grip on the audience. In fact, it's evident that the author had long lost its grip on the logic of the characters—both of them—that could lead to the resolution of their ideological conflict without invoking the deus-ex-machina ending.
Perhaps the most saddening thing about this manga is that the author's ideas conflict with their realization. His intention is to let us ponder on the nature of humanity: what makes us human. This intention is sabotaged by the clear-cut and comical contrast between the two main character arcs that portray people who are clearly NOT human enough. In fact, almost the entire supporting cast feels far, far more human than the leads under the looking glass of the author.
What could've been done to avert this? For starters, it would be great if instead of ushering in shock value and violence porn we would've gotten a better picture of the antagonist, something that humanizes him. Having seen the chain of events that shaped his mental condition would let us peer more closely into his troubles and see if it's something we can relate to, something we have experienced in our lives. It would do well if would could be more familiar with his situation. It would do well if we could see the lead-up to his first kill to see the emotions going through him, see him overcome that barrier of humanity, see if there's anything else left in there and how that little sliver of goodness manifests and transforms over the course of the story. What we're shown is just an after-effect that forces us to fill in the blanks by ourselves. It's not necessarily a bad thing to leave things untold, but as we've skipped the fundamentals of the character, it turns from an intellectual riddle to coping with lazy writing.
Elaborating on the relationship between the antagonist and his friend instead of cutting it so abruptly would also be a good thing. We haven't been given a reason to care enough about their friendship, so the dramatic moment at the end that involves it naturally loses the oomph. This would also give this other character more credence and enrich the story with his own inner conflict: do I help my friend or do I help bringing him down? What *is* the right thing? Unfortunately, the character in question decides this very quickly and never really looks back.
It would also do well if the protagonist didn't have such an exemplary Lawful Good* personality. No amount of bad looks and silly names can cover the innate boringness of an impeccable idealist. The only struggle he has to overcome is the feeling of guilt for not saving more people than he has. But he's no Superman, and there isn't nearly enough effort taken to show him questioning himself or feeling the complex and dark emotions over his newfound powers, condition, and motivation like a normal human being would. Instead, as soon as he gets his powers he just goes and does the right thing while still trying to live the life of an invisible member of the modern society—and that's about it. It's only at the very end that we get to have a glimpse at his motivation, but it's treated very matter-of-factly and isn't nearly enough to flesh out his character arc.
To summarize, it is a nice sci-fi action manga for people who enjoy the more violent and realistically drawn sci-fi without character-based side-plots or any deep thematic exploration. For the fans of the latter, Inuyashiki will inevitably appear all too shallow.
* See en.wikipedia.org/wiki/Alignment_(Dungeons_%26_Dragons)#Lawful_good
