Not much is known about the Cannon Shooter, although he is accompanied by a monkey. The Cannon Shooter is a separate Pirate Explorer Class, similar to the Dual Blade.
The Cannon Shooter was just a regular Pirate who was sailing on his ship, until a Jr. Balrog appeared out of nowhere and attacked the boat. The Cannon Shooter and company were unable to fight back, and eventually the Jr. Balrog knocked the Cannon Shooter far into the water where he/she nearly drowned. Fortunately, a monkey saved him and brought him to Coco Island.
After getting acquainted with the monkey, the Cannon Shooter meets a man who has been stranded on said island for a long time. The Cannon Shooter does several errands for the man, and eventually the three of them launch in a cannon to Nautilus Harbor.