There are series that make you think, series that make you sweat, series that make you cry and question your life. And then there are series that just make you want to get up and boogie. Blue Exorcist is one of the latter. It isn't weighty or smart, but it is loads of fun.

It doesn't get that way by breaking the mold. In fact, the show seems inordinately fond of the mold. The series is fashioned primarily from the oldest and moldiest shonen tropes its creators could find. Thus Rin is a half-demon driven to fight his own kind, enrolled at a special school for magically empowered teens. He has a tragic past, meets and befriends a gallery of quirky potential allies, and must hide his identity from those around him. There is, quite naturally, a Human World (Assiah) and a Demon World (Gehenna), the barriers between which are of course weakening, allowing demons into the human world (but not vice versa, curiously enough). Rin is driven by an overriding goal (to defeat his father) that others ridicule as a pipe dream and has a reputation as a dangerous punk amongst his peers. This despite, again quite naturally, having a kind heart and an iron sense of justice.

If you just dislocated your jaw yawning, that's perfectly understandable. You'd have to try really, really hard to be surprised by anything Blue Exorcist brings up. Its appeal lies not in creating something new, but in doing the same-old exactly right. Take Rin. He's one enormous punk-with-a-heart-of-gold cliché, but he has both a dangerous, feral edge and an inherent humor that make him an endlessly entertaining one. Likewise his tragic past and quixotic quest are given weight and urgency, respectively, by a finely-tuned pair of opening episodes that establish with occasionally terrifying clarity the dangers and the stakes of Rin's demonic origins. Subsequent episodes mostly abandon the intensity of those first episodes for (of course) semi-humorous tales of supernatural school life, most focusing on Rin's interactions with various classmates, but the opening shadow persists, darkening the predominately light mood and providing a compelling reason for Rin's occasional outbursts of scorching intensity.

As for the humorous half of the half-humorous, Rin accounts for most of it, playing easily off of the disjuncture between his black origins and deadly mission and his nature as a perpetual screw-up. Later episodes may be short on substance, particularly when they start revolving around things like cute kitchen demons, but so long as Rin is front-and-center they're never less than amusing. And no matter how goofy it grows, the series has the smarts to keep a few genuine emotions (love-interest Shiemi's insecurity, rival Ryūji's helplessness-spawned rage), straight-up tragedies (Shiemi again), and flashes of real violence nearby to jolt us from our doldrums.

Tensai Okamura has helmed enough amiable cliché constructions (Project Blue Earth SOS and to a lesser extent Darker than Black) that he is well-versed in the mantra of all genre-bound successes: "Execution, execution, execution." No matter how skillful your distillation of the better qualities of a chosen genre, it means nothing unless executed just so. Okamura is very good at the "just so." The first episode is a study in slick animation and slicker action, looking every bit as smooth and regular as Rin's life is at that moment. He tries—and fails spectacularly—to get a part-time job, beats the tar out of some sadistic punks, and argues with his dad the crazy priest—all in clean, nearly flawless animation. When the weirdness comes, as it must, it comes in fluid, freaky, and shockingly unrealistic form.

From there the action moves to True Cross, where different rules hold sway. True Cross is an impossible pile of European architecture, building heaped upon buildings in a labyrinthine mess that stretches into the sky and can only be successfully navigated using magic. It's an entirely different world and Okamura treats it entirely differently. Rin's design grows simpler and rougher, as do his often comic movements—a reflection of his brightening personality, itself a reflection of his brightening situation. The people surrounding him, all of them exorcists, grow more wildly individualistic, almost silly in some cases. Humor is as important as angst and action here, and Okamura's energy, choice of colors and increasing fondness for comic simplification reflect that.

His true skills, however, clearly lie in action. Even his smallest fights are little technical marvels, and episode two's big battle is a wringing, sprawling thing during which he combines demonic transformation (and its accompanying power-up coolness), deliberately incongruous CG creepy-crawlies and extreme, lovingly animated expressions as if to the genre born. From UVERworld's rocking opening to 2PM's new-wave closer the series looks and sounds great, but it only really peaks when the score swells darkly and the swords and bullets and bodies start flying. Even Rin, as crazy cool as he is, is infinitely more so when he's Action Rin: all pointy teeth and ears and insane, fiery eyes.

You'd think, as well as he handles it, that Okamura would cram the series from stem to stern with balls-to-the-wall action. No such luck. If Blue Exorcist has a lethal flaw (besides Rin's bland brother Yukio), it's its strange reluctance to embrace full-on action. It dallies so long with funny filler, student rivalries, and puppy love that it sometimes seems to have forgotten that its primary purpose is to kick ass. And then, of course, it will kick some—just to remind us that it kicks it so very, very well. Now, if only it would gel more solidly into a compelling whole, it'd be perfect. Or as perfect as a series without a lick of originality can be.