Who exactly is he?

"Actually, the Rose of Death was just a book our captain's father wrote when he was younger. He roughly described a power like that and stopped writing after that. Then the captain was born and he thought the Rose of Death was pretty interesting, so he continued writing and described the Rose of Death in more detail when he was younger…"

"Such as how the members of the Rose of Death wore windbreakers with a subtle rose print on them and silver masks - all these details were written when the captain was a few years old. The leader of the Rose of Death, Black Widow, who loved men and was bloodthirsty, was also made up by the captain!" The devotee laughed.