Misadventures of Flameheart Jr
As he sought to build a name and reputation for himself, Flameheart Jr was brought to see a contact of Isidro's, an old woman who promised a long lost treasure that she'd kept secret since her childhood.
The map led him and his crew in the Wilds where he dug up a Cursed Chest. As they leave, they found themselves ambushed by other ships. Making a desperate attempt to flee from the pursuers, Flameheart Jr sailed the Silver Blade into the fog of the Devil's Shroud.
Source
Tales From The Sea of Thieves