There's absolutely nothing in Cerberus that hasn't been done before. It's a typical shonnen manga: a guy (Kei) gets the powers from a supernatural entity (Yukifusa, a cool hellhound) to protect those around him from demons;, he is strongheaded, dumb, has bad attitude, but he is a nice guy and he has a childhood friend who is clueless of her powers and he cares about her deeply. Does this sound familiar? Anybody who has seen a fair amount of anime must have come across these kinds of elements, and this manga adds nothing new to the mix. In fact, the art is truly poor if not pathetic, the story plot is decent at best and the characters don't go beyond their steriotypes And yet I can't stop reading. I actually don't know why, for some reason it's kind of entertaining. Could it be that it's so bad that it's good? Maybe, yet the art is so annoying that it's hard to believe I can put up with it.
So yes, it's bad, but there's one thing I can't deny the manga does well: push the cool button. You see, the transformation the main character goes through to become a Grave Protector (or keeper, they always shift it) is one of the coolest I've seen, and that's why I started reading this manga in the first place. It's so incredibly cool that you just wish this concept was done by a better mangakate, one that could actually pull off a better concived story plot, characters and drawings, but instead... we get this.
It's very predictable, it's a pain to stare at the dreadful drawings when you have seen much better (I'm looking at you CLAMP), but the Kei's powers are so cool that I can't stop reading it. I want it to become better, and sometimes I have to admit that the manga is able to draw a smile out of me (mostly due to Yukifusa, the only character that is kind of interesting and refreshing), but so far there is no real indication that it will be more than what it already is.
It's too soon for me to judge it, as Rave Master started almost equally shaky and became epic later on, but I don't hold much hope. I'll most likely keep reading (and update this review once I get through it) just because it's kind of addicting, but there's no denying that, at least for now, it's a bad manga all around.