1- “Red Flag” X Drake is the son of the Marine-turned-pirate Diez Barrels, and as a young adult was called Dory. He was physically abused by his father, and when the Donquixote Pirates invaded Barrels’ hideout 13 years ago, he abandoned Barrels’ crew as they were trapped and massacred.
2- Currently, he’s the captain of the Marine Secret Special Unit SWORD. In order to go undercover as a pirate, he publicly defected from his position as rear admiral and founded the Drake Pirates.
3- In Drake’s endeavor as an undercover spy, he and his crew became subordinate to the Beasts Pirates. His treachery was eventually uncovered, however, leading him to attempt to ally himself with Monkey D. Luffy.
4- Drake’s name is based on real life privateer Sir Francis Drake.
He shares his name, sideburns, and voice actor with another character. However, this character is still a member of the Marines and is also non-canon.
5- In SBS Volume 64, Oda drew the Supernovas as children. Drake is shown wearing a small tattered Marine uniform, showing that he aspired to become a Marine since he was very young. He appears to have been a playful and cheerful boy, as opposed to the stern and serious man he grew up to be.