The Black Rose Pirates are a small group of pirates who are all devil fruit users.
Tadashi is the captain of the Black Rose Pirates who ate the Mira Mira no Mi (mirror mirror fruit) which allows him to create mirrors. Tadashi believes that people with devil fruit powers are superior to normal people and created the Black Rose Pirates so he didn't have to be around people without devil fruit powers.
Masashi is the vice captain and ship wright of the Black Rose Pirates who ate the Kin Kin no Mi (Gold Gold Fruit) which allows him to turn parts or all of his body into gold. Unlike the rest of the crew Masashi doesn't like his devil fruit and joined the Black Rose Pirates in the hopes of finding a way to remove it.
Izumi is the chef and navigator of the Black Rose Pirates. Izumi is a terrible chef and only got the job because she refused to join otherwise.
Harumi is the doctor of the Black Rose Pirates. Harimu doesn't like the other members of this crew.