Rathbone was a friend of Ramsey, joining him in his maiden voyage through the Devil's Shroud and to the Sea of Thieves on the Magpie's Wing.
Born to a businessman and raised to follow in his footsteps, Rathbone was a calculated individual who a sharp memory. He built up his own business but a combination of his own greed and a habit of undercutting his rivals eventually led to having a warrant out for him. Disgraced, he joined with the thieves and criminals he'd once employed and made a name for himself as a pirate.
How he and Ramsey first met it unknown, but they did hold a respect for each other and sailed many times together, proving to be a formidable duo.
Rathbone had other plans when it came to the pirate's life, especially in the new frontiers that the Sea of Thieves offered. He sought to obtain all the riches for himself and didn't much approve of Ramsey's sway toward the mystical and magical mysteries of the world. It was him who gave Stitcher Jim the location of a stash of maps that showed the safe entry to the Sea of Thieves, and he would go on to later betray Ramsey.
He set up the Gold Hoarders Trading Company to collect all the locked chests that Ramsey had hidden, giving his underlings limited access to the Skeleton Keys he stole from Ramsey.
As the Company grew, Rathbone had no need to stay in the Sea of Thieves and lived as a wealthy individual on a fine estate elsewhere.
Tales of the Shores of Gold brought him back to the Sea of Thieves and would prove to be his demise. He found the fabled island, sat upon the Throne in it's deepest halls and plotted to leave with all the treasure he could. As he left on his loot burdened sloop he was confronted by ships that were part of the Pirate Lord's Alliance. They fired upon his ship and he sank, but a curse had already taken ahold of him and he spent countless days and months taking back his sunken loot to the Throne Room of Tribute Peak. It was here that he began his slow transformation into The Gold Hoarder proper.
As a Skeleton Lord he kept some semblance of his mind despite it being driven by a greed for gold and wealth, and kept in contact with the members of his Trading Company who in turn brought him tributes.