It's a week until Necronomidol's big show and, practicing at a dance studio in Tokyo's Shinjuku Ward, the four members make a decision to change one line from "We've come to bring about the Apocalypse" to "We've come to enact Armageddon." Manager Ricky Wilson agrees; another problem solved.

The four-member Necronomidol claims to be Japan's first occult-infused idol unit, and its members are still tweaking lyrics and stumbling through the choreography for their new song, "Skulls in the Stars," but 31-year old Wilson is calm. He supplies the concept — in this case, a tale of cosmic horror set to horror disco — and the members make it their own. Besides, even if they stumble on stage, imperfection is a selling point in the idol world.

At times like this it pays to be the underdog. The unit's low visibility allows it the freedom to experiment — and possibly fail — in ways that established acts could never risk. Necronomidol and other self-produced underground idol groups share more in common with DIY punk than polished pop — and they're the place to be if you like your music raw.