Rikuo is the 'third heir' of the powerful Nura clan. A clan of youkai (supernatural monsters, basically) to be precise. But he is mostly a human, and only 1/8th of him is youkai. He doesn't want to take command of the clan when he turns 13 (the youkai age of majority). Rather, he'd be a normal human boy, amongst other normal humans (chiefly his classmate Kanna). However, various events conspire against him, and he is forced to man up to his legacy.
It turns out that the youkai clans are organised like the yakuza, with sub-clans holding territory for the main clan, with reciprocal vows of protection and assistance to cement the bond between clans. This is why the Nura clan is so powerful: they have allied with many powerful clans that they absorbed -- sometimes after a fierce battle. This is also why Rikuo's wish to be a normal human is viewed with suspicion, and many doubt his motives when he decides to embrace his youkai heritage fully.
The series has two arcs. The first arc introduces the main characters and shows how Rikuo copes with being a youkai heir as well as a normal middle-school student. He saves a head of one of the sub-clans when he is in his youkai form, and then decides that he will rise to be the head of the Nura clan after all. And then he gets involved in a rebellion by a clan head who wants to verify Rikuo's motives. Unfortunately, his classmates get caught up in it all too, but of course Rikuo needs to keep his youkai side hidden from them (especially since they have formed the 'supernatural patrol', spurred on by a youkai-otaku). In the end it all turns out for the good, and Rikuo gains the approval of some of the clan heads.
The second arc details an all-out attack on the Nura clan by a bunch of youkai from Shikoku. Their leader is a rather ruthless type, which makes the contrast with the Yakuza-like Nura clan even bigger. Rikuo's grandfather goes on a yourney (to Shikoku, actually), so it's Rikuo who has to call the shots. He is cautious, which is not to th eliking of the more hot-headed leaders who would want to charge in blindly. But Rikuo cements his alliances and starts to form his own 'Night Parade of a Hundred Demons'. Not by using his comrades as throw-away tools, but as valuable companions who plead mutual assistance. Obviously, that wins out in the end.
Visually, it's not very inspiring. The character designs are not that detailed, the animation isn't very smooth -- but it's all servicable. Some of the monsters have been detailed with great care, though.
The voice acting is pretty cool. Especially the difference between the voices of Rikuo and his youkai self (done by the same actor!) is nice.
- Interesting take on yakuza-like monsters;
- Solid story arcs.
- Visually not very inspiring.
All in all, enjoyable. I'll give it a 7.