666Satan

From Animepedia

666Satan is a shounen manga by Seishi Kishimoto, the younger twin brother of Masashi Kishimoto. The series began publication in 2002, and has chapters released on a monthly basis. The series was renamed O-Parts Hunters due to the religious themes of the series.

Plot

Ruby Crescent's father was a great treasure hunter, and upon his death, she has taken up his work in finding the mysterious O-Parts, magical tools of an ancient and advanced civilization, which mysteriously and suddenly ended. In a seemingly post-apocalyptic world, Ruby encounters a young boy with a dark past, named Jio Freed. When the two of them are confronted with by a group of malicious O-Parts tacticians, called O.P.Ts, lead by a man proclaiming himself Satan, Jio reveals that he too is an O.P.T, and when in danger, he is taken over by another personality, that of Lucifer, the true Satan, branded with the number of the beast, 666, in his forehead.

Characters

Ruby Crescent

Jio Freed