666 Satan(satan 666) by Seishi Kisimoto
You did not hear wrong, seishi is actually Masashi's younger twin brother. They're comic styles are pretty similar, since they grw up together they drew together. The comic is not yet out in English, but they do have some transalted chapters online.
The story is about a boy name Jio who's actaully part devil. He ends up meeting a girl 'Ruby' who continues the work of her father. The OPT, a group of baddies are out to collect all of the 0-parts. Each o-part has it's own special ability, and can be in good use when you put power into it, almost like chakara. They fight guys with water blasters,an excessive tongue ring opt, and he even makes a new friend.
I'd give the comic a 8/10 just because of th art and the amazing detail in the pictures. The story isn't too original, but the characters are memorable. It's great to see seishi isn't afraid to release a new comic that has a similar art style to Naruto. This is definately a comic to check out if you like Naruto n_n