Now that represents a solid return to form for Ao no Exorcist. No other currently airing series does filler as well, but last week’s was pretty flimsy even by those standards, and it’s nice to get back to some plot-advancing development.

Mind you, there was plenty of amusing stuff happening here. We got to see Shiemi in a school uniform, for starters. Turns out it suits her rather well, and she has a, shall we say, generous figure that catches every boy’s eye. It’s nice to see her slowly being integrated into the modern world after being holed up in her garden for so long. It’s also nice to see some real development between she and Rin, too, as that’s certainly the pairing that I’m rooting for here. In a way, the vibe reminds me of Fruits Basket – with Rin as Kyo, Yuki as, well – Yuki – and Shiemi as Tohru. In that case I rooted for the hot-tempered, screw-up outsider with the heart of gold over the overachieving, conceited “good boy” – and here, too.

The premise for all this is a trip to “Mepphy Land” to chase down a mischievous ghost – in this mythology defined as a demon who’s possessed the vapors of a dead person (in this case apparently an ill little boy who died in his PJs). There are lots of good things about this setup, not least of which is that it gives the crack animators at A-1 Pictures a chance to have great fun with ridiculous Mephisto theme park attractions, never forgetting of course the Mepphy Shop. With the gang of eight students and two teachers (Yukio and Tsubaki-sensei) on hand, everyone splits up into pairs to go ghost hunting, and fortunately Rin and Shiemi end up as a team (bad move for you, Yuki).

The mischievous ghost manages to get Shiemi one-on-one while Rin has other matters to attend to, and proves himself to be a pervy little fellow. After feeling her up, the ghost boy takes Shiemi for a dizzying ride on the teacups as Rin deals with problems of his own.

Into this steps Amaimon, finally emerging from the cameo stage to full-on action. We know he’s Mephisto’s otouto and he calls himself a Demon King (and later he’s called the Earth Lord) so there’s a little more background on Mephisto as an omake. His job is clearly to test Rin’s limits, both in terms of power and self-control, which he does first by stealing his sword and teasing Rin mercilessly by unsheathing and re-sheathing it (Rin’s powers with it) and then by beating the crap out of him. Well, mission accomplished – he manages to piss Rin off to the point where he loses himself in rage, but a cry for help from Shiemi (trapped under some debris from the struggle between Amaimon and Rin) snaps him out of it. And the arrival of Shura on the scene causes Amaimon to drop the fight – for now.

Who? That’s right, one of our mystery students has been unmasked, and “he’s” a she. It’s Shura Kirigakure (Satou Rina), Upper First Class Hottie Exorcist. She’s an inspector from the Vatican sent to investigate “risks” in the Japanese branch, which I take to mean Rin. She’s a sword-wielder too, and clearly she’s going to be a force to be reckoned with. With that fight avoided for now, things are settled as Shiemi has sorted things out with Ghost-boy on her own. Apparently getting to second base and tearing up Mepphy Land was enough to satisfy him for now, and with an “Arigato, Onee-chan!” he disappears.

All in all this ep worked equally well as an entertainment and as a canon episode. Amaimon finally got some real development, and proved himself to be both extremely formidable and a bit of a smart-ass (runs in the family, clearly). We finally have one mystery student revealed, with only Bunny-boy left as a cipher. We know more about Rin’s sword, thanks to Amaimon – the scabbard is the gate between Gehenna (where Satan’s flames reside) and Assiah (where Rin’s body does). Maybe best of all we got to see Shiemi running in a school uniform, and she certainly shimmies like jelly on a plate. Ao no Exorcist definitely behaves like a series that has all the time in the world to tell its story, but it sure is nice to get a substantial episode like this sometimes.