Once a pirate lord, and a heroic captain, Davey Jones fell in love with an eldritch god of the sea, Calypso. In their relationship, Calypso took him and his ship, and charged them with ferrying lost souls to the afterlife. And while he became immortal in a sense, Captain Jones was unable to return to land for ten years. But, he fulfilled his new duty with grace and loyalty. That is, until a decade later, when he returned to shore to look for the goddess, she was no where to be found. In a fit of rage, he showed the Brethren Court how to bind her in a human form. And in a result they captured, and cursed her to live an eternity as a human. The seas now belonged to the race of men, and Davey Jones would continue to haunt the ocean. Not as its ferryman, but as a cursed ghost and executioner.
Centuries would pass, and Davey's name would go down in history, as the Flying Dutchman would appear to prey on vessels doomed to his crew. And while some ships might have proven to be a match for his battered frigate, or ran the risk of outrunning him, Davey would unleash his ultimate weapon. The last of its kind, the Kraken. A monstrous tentacled beast which is said to devour ships and crew whole, while sending the bulk of said crew into the depths, or in Davey Jone's Locker- a place in-between the world of the living and the dead. Alternatively, those that were "fortunate" enough to survive their doomed fate were greeted by the captain, and given a choice. To survive their inevitable death and serve his crew as cursed fish like entities, and eventually be a piece of the ship (should they serve long enough) Or die with the rest of the crew. However, this was also not a guarantee. As on a whim or on his mood, Davey Jones was known to simply spare no quarter and execute everyone on board.
While Davey Jones was originally a man, his cruel deviation from his responsibilities had cursed his ship, his crew, and himself into twisted fish-like monstrosities, which quickly worsened overtime, leaving much of the crew unrecognizable, or worse became apart of the ship itself.
While the curse was immortal, Davey Jones could in fact die. For upon his intial binding of Calypso, Davey managed to cut out his heart, and sealed it into a chest~ to bury it in an unmarked location that only he and his most trusted officers would know. For if the heart were to be destroyed, Davey would surely die, and the curse of the Flying Dutchman lifted for any afflicted.