According to Bloezoeng, Commodore Reyner of the Yellowjackets has need of a capable adventurer for what promises to be a grueling task. If you would answer the call, make your way to Limsa Lominsa and present yourself before the commodore at the Coral Tower on the upper decks.
Reyner informs you that Sastasha has been overrun by an unidentified group of pirates...who may in fact be monsters. Recalling the way you once drove the Serpent Reavers from the caverns, the commodore is confident that you will be able to quell the new threat─whatever it is. Make your way to Sastasha in western La Noscea, and report to D'perjha, who stands guard by the entrance.
D'perjha has briefed you on the current situation. In the absence of new intelligence, you have no choice but to play it by ear. Venture into Sastasha, and eliminate the threat within. ※Sastasha (Hard) can be accessed via the Duty Finder.
Deep within the bowels of Sastasha, you corner the hideously transformed resurrection of Captain Madison who summons forth the Kraken to do his bidding. However, the dread pirate's dastardly plan rebounds upon him when, with a flick of its tentacle, the creature sends him flying. Setting aside this bizarre scene, you and your comrades engage the gargantuan sea beast, and succeed in vanquishing it. Your mission thus accomplished, make your way back to the outside world and report to D'perjha.
D'perjha is shocked to learn that the monsters that had overrun Sastasha were none other than the Serpent Reavers. Having informed you that their bodies will be collected for analysis, the Yellowjacket bids you report to Reyner, who has since arrived in Aleport.
No sooner do you begin speaking with Reyner than the body of one of the jellyfish men arrives from Sastasha. The scholar Ceana believes that its hideous form is the result of overexposure to aether, most likely due to repeated tempering. In light of recent developments, Reyner pledges to tighten security around Aleport.