Mr. 6

Mr. 6 (ミスター・シックス, Misutā Shikkusu) is the partner of Miss Mother's Day and a Frontier Agent in the Baroque Works rankings. He was first mentioned by Nefertari Vivi, who explained how Baroque Works was organized to the Straw Hat Pirates. Neither him nor his partner are seen in the series. His ranking suggests that he is considerably stronger than the other Frontier Agents.

Trivia

 * In an SBS, a fan asked how Mr. 7's appearance would change if he got promoted to Mr. 6's position. As Mr. 6, his sunglasses and eyebrows would take the shape of 6's.