

He was raised as an orphan on a secret island hideout of a criminal combiné, where he learned all his criminal skills, including developing his special masks, before killing the head of the combine.

He was later given a more “Robin Hood”-like persona and was shown stealing essentially from criminals, in order to soften the series’ violence and amorality.

In his first appearances, Diabolik was a more straightforward villain who did not hesitate to murder anyone in order to accomplish his deeds. He seems to have a deep knowledge in many scientific fields, including chemistry, mechanics and computers. He typically steals from criminals (and has no issue with killing them if need be, but rarely, if ever, kills the innocent or the police), and has a set of lifelike masks which he uses to fool his opponents, assuming every identity at his will.
