A pirate of Spanish origin, Jack’s father was a renowned weapons manufacturer and his mother was a musician. Jax grew up as a very intelligent child who was fond of hearing pirate stories and longed to live himself and enjoy all the adventures he had heard tales about. He fantasized about getting lost in the sea, and being found by a pirate ship. During a trip through the Balearic Islands, the ship in which he was traveling was shipwrecked and Jax was left adrift in a part of the boat.
However, he was thankfully found by an Italian merchant ship who sold musical instruments, weapons, and jewelry. Impressed with his luck and despite knowing that his parents were alive, he decided to hide his origins and live life to the fullest with adventures on the open sea. Due to an epidemic of smallpox aboard the ship, Jax’s employer was forced to exchange the crew including Jax for food. However, Jax had learned the real pirate life by this time and managed to survive due to his extensive knowledge of weapons and music, which was actually his first great passion. In one ship attack, Jax gained the admiration and complicity of Fury who took him to meet Captain Jack Black and he was welcomed as an important part of the Jolly Roger’s crew.