|Romanized Name:||ki aoi|
|English Name:||Atsuko Aio|
|Affiliations:||Blaze Dragon Pirates|
|Epithet:||Black Sword (黒剣 Kuroken?)|
|Age:|| 19 (Debut)|
21 (after timeskip)
|Height:|| 178 cm (5'10") (debut)
181 cm (5'11") (after timeskip)
He was the first member to join the Blaze Dragon Pirates, and, to date, is considered the largest threat and most dangerous member in the crew after Riko. His fame as a master swordsman and his great strength, along with the actions of his captain, sometimes led others to believe he was the true captain of the crew earlier on. He is one of the top three fighters in the crew alongside Kazuki D. Riko and Hayato, and his dream is to become the greatest swordsman in the world. Aio has the second highest bounty of the crew 150,000,000
Aio initial appearance is a black suit that he always wears except on special occasions.Their big eyes mischievous, and he appeared have pointy ears. He carries a large sword black on its back and over time he began using two swords to fight.
After the timeskip, he becomes known around the world as the "Black Sword" due to their tendency to wear black clothes. Their clothes consisted of black trousers with a black belt with a Silver buckle, a black v-necked shirt which were used under a black trench coat with grey lining down the gloves and black boots with silver plates to protect your Shins. It has a silver plate used in his jacket, which was on his left side and a pair of black fingerless gloves. He uses a strap that goes over the right shoulder and under it to wrap around the left side, which keeps his sword harder the Black Force, then his Strong Point too.
- Aio love fishing.
- Aio tried wielding three swords but gave up since. Apparently, it felt like his teeth would fall out.