The Cobleighs and their associate Julian held a deep-rooted rivalry with Edward Kenway, a young Welshman living in Hatherton, near Bristol. In the summer of 1711, Julian, Tom, and Tom's son Seth Cobleigh had a fight outside the Auld Shillelagh tavern with Edward, who was trying to defend a drunken woman called Rose from being abused sexually by Tom. Despite quickly gaining the upper hand, the trio were stopped by Rose's employer, Caroline Scott. Two days later, the group slaughtered two of the Kenways' sheep and placed the carcasses in front of the Kenway house in order to scare Edward, who reacted badly to the provocation. Edward's father refused to let him retaliate, explaining that the Cobleighs and many merchants of Bristol had joined the Trade Organisation, an association of tradesmen protected by "powerful men".
Some time later, in Bristol Harbour, Cobleigh witnessed Edward being thrown into the sea by Wilson, Matthew Hague's henchman, when the young man tried to court Hague's fiancee, Caroline Scott. Giving his hand to a disoriented Kenway in order to seemingly help him get back on the docks, he punched him in the face with a smile, throwing him back into the sea. The rivalry between the Cobleighs and Edward reached a head when Tom and Julian became involved in a plot to kill or otherwise remove Edward from the area after he had upset their Templar masters, Emmett Scott and Aubrey Hague.
In late 1712, a hooded Julian, Tom, and Wilson burned down the Kenway farmstead while Edward's parents were sleeping inside, and while Edward was in Bristol embarking on his life as a privateer. Coming back to Hatherton due to his departure being delayed, Edward tried to stop the Templar and his allies, but the group pinned him to the ground, beating him and subsequently left.
After having alerted his parents, an infuriated Edward returned to the Auld Shillelagh, searching for the group and taking a sword from the wall. Once Julian, Tom, and Seth stepped into the tavern, Edward ran Julian through with the sword, killing him before chasing the Cobleighs. Knocking out Seth, he then gave chase to Tom through the farmlands. Kenway caught up with him and disarmed him, but Tom was killed by Wilson, in order to keep Edward from interrogating him.