In the manga, Diavolo seeks absolute security and superiority by eradicating all evidence of his past. He is fiercely protective of his secrets, resorting to violence, even against his own family, to safeguard his identity. Living a shadowy existence, Diavolo issues orders through intermediaries or digitally, ensuring he remains unseen. His fixation on obliterating his history and maintaining secrecy is a defining trait of his character.