Well, after attending a "Pre-war" gathering in game (which as shown in screen shots, a Marceline guild member, the Captain of the Casa Muertos guild, and Captain Walter played a role in) I learned a little bit more about this.
The Captain (Rott) came to Tortuga. Rott tried to sound innocent, and wanted to keep things secret from Marceline. He tried to tell us to help him dig up some "useless" items on Port Royal in the upcoming week.
Once he left, a Marceline member showed up. She informed us that Rott used to be a friend of Walters, but that is not the case now. She also said he was up to no good.
Finally, Walter said a lot more. He informed us that, during the attack against the EITC (when people sunk ships with the GMs), Rott was there. Rott ended up sinking to his grave. He also mentioned that, what Rott was after was protecting the Caribbean from Jolly Roger's magic.
So apparently, Rott struck a deal with Jolly Roger, to be brought back. In return he has to remove the objects from Port Royal (which should let the Muertos Moon curse return).
Regardless of if the quest is completed, Disney will more than likely continue with this approach if this is the case. It could very well be the next chapter close to release.. you never know
