It's an urban fantasy shounen series, albeit less fight-orientated than usual for that genre. It's mildly horror-tinged and willing to go places that other shows might shy away from (e.g. different kinds of sexual exploitation). It's pretty good. I probably won't keep the episodes, but I enjoyed it and I'd watch a second season.
Our why-aren't-they-schoolboys heroes work for the Inugami Detective Agency instead of attending school. Why not send them there? The show never even considers this question, but I suppose we're meant to assume that monsters get a free pass. Inugami himself is an adult and a tanuki who can transform himself into anything, e.g. turning his hand into a gun that fires actual bullets. Wow. He's the easy-going boss. Our child heroes are:
1. KABANE (half-ghoul) = emotionless, helpful, liable to agree to anything. He has no social skills whatsoever and could be mistaken for autistic, but his straightforwardness and lack of personal desire makes him quite popular anyway. He might be incapable of lying, for instance. He's also unkillable. Burn his body to ashes and he'll just grow a new one.
2. SHIKI (spider-boy) = wants to be aggressive and rude, but underneath that he's a good boy. He's also short-tempered. I didn't like him at first.
3. AKIRA (yuki-onna) = gets upset when anyone mistakes him for a girl. (He's girlier than most actual girls and is liable to faint and wet himself.)
The tone is comparatively light, but the storylines really, really aren't. All three of our heroes have a backstory that in a grimmer show might get the audience opening their wrists. What happened in the past to Shiki's mother and Akira's twin brother is extreme even for anime. The show handles it respectfully and never lets the material become tasteless (which it could easily have done). Incidentally, I have a theory that Shiki's mother ate his father. This is a counter-reading that flies against the story's intentions, but it fits the death dates, the monster biology and the observation that most humans aren't sexually attracted to spiders.
The monsters can look a bit goofy, e.g. the mosquito women, but that's okay.
The gender balance is a mild negative for me. Everyone in the Inugami Detective Agency is male, although in fairness they'll end up semi-adopting two girls. (Different circumstances, different weird problems. Kon is the perfect match for Kabane, because they're both hopeless space cases. A Kon-Kabane conversation about anything that needs emotional intelligence is like the blind leading the blind.) Female characters are often scary and/or drawn with off-putting mouths or smiles. (The show's art style has a knack for women who in real life would make you want to leave the room.)
I wouldn't call this a must-watch show or anything, but it's pretty good. Sometimes it's funny. It's capable of particularly good scenes and episodes. You could definitely do worse.