Marisabel meets with the Twisted Knife
Marisabel decided to sell the Whispering Chest to any merchant or vendor willing. As she was trying to find someone, her ship is assailed by The Salty Hippo and another ship. They fought them off and took Cole, the captain of The Salty Hippo, captive.
Cole revealed himself as a member of a group of bounty hunters known as The Twisted Knife. Whilst in the brig, he elicited knowledge about Flameheart Junior and the Whispering Chest, revealing that they were hired by a patron who had sent many before to retrieve the Chest.
Source
Tales From The Sea of Thieves