Kamichama's biggest flaws come mostly from the story. While the offbeat humor fits in well in the first volumes, it becomes increasing inappropriate as a more serious plot is built upon. Most notably, the cast's antics and the slapstick humor feel severely out of place throughout the climactic volume, so much that I began to wonder if it was in Donbo-san's contract to write jokes for every chapter.
But that's small peanuts compared to where they really dropped the ball. Koge Donbo forgot how to write a plot twist. More to the point, Koge Donbo forgot how to write a plot twist until the final chapter and crammed 20 of them into 4 pages without any consequences or significance to the story. Now I can swallow a lot, but this was just too much. It defied the laws of realism established by the storyline. Because the manga had good buildup and was intriguing for it's longevity, I won't rate the story too poorly, but the last chapter was definitely enough to give it a 4.
The characters were not much better. Karin was a fun ditz for a few chapters, but she never... and I mean, NEVER grew past that stage. She is constantly irritating, has an annoying way of speaking, and generally has nothing that redeems herself of her flaws. Rather than a main character, she is toted around by the manga-ka as a love interest whose only ability is to be ditzy, cute, and eventually nab her man. I'm serious she does nothing else.
Other characters were either incredibly flat, completely unbelievable, or demanded more time be spent on them. Villains are sometimes treated with gravitas but most the conflicts are jokes. The characters are supposed to be in mortal danger but there is never a sense of that in their fighting. The only redeemable character in this mahou shoujo farce was Kirika, if only for offering a slight bit of depth and a generally compassionate role for the reader; a drastic change from the rest of the cut-and-dry cast
At this point, one would assume at least Koge Donbo's laudably adorable artwork would save this. From the first volume alone, you would guess right. Her trademark style leaves fits phenomenally with the story she's providing, even though her SD-drawing hasn't improved a scratch from her previous work. All goes well, but as the series hits its final stretch, the quality of the art takes a drastic nosedive and looks like that of an amateur dojinshi artist attempting to copy the manga-ka's style. It's downright embarrassing that a manga could provide such consistently wonderful A-ranked art for several chapters and then just bomb.
Now finally, I didn't hate Kamichama Karin in its entirety. The ending was horrible, and apparently there's a sequel but after all it pulled in the final chapters, I doubt I can bring myself to give it a look. For what it's worth, Koge Donbo sets up a fantastic story. It's not too dark, has a good amount of humor, and falls together quite nicely, but the rushjob finale and lack of gravitas to moments of drama bring the whole thing down more than I would have liked it to. If you're a fan of anything mahou shoujo, I'd recommend trying it, but don't expect too much from it, and don't expect anything from the ending.
Overall, I give Kamichama Karin a 5 out of 10.
