666 Satan is a Manga I am about to start reading its called O-Parts Hunter in English cause america cant take alittle word like Satan in the title but whatever>_>
It is created by Kishimoto Seishi The Twin brother of Naruto Creator, Kishimoto Masashi O_O
I heard it is a good manga for those who like naruto because it is similar in style which is why im showing it here XD I dont think there is a anime of it.....Yet >.> but anyway here is the link to all the chapters starting at the first:
http://www.onemanga.com/666_Satan/1/