This quest will teach you how to recruit new lieutenants for your ship. You can recruit pretty much any enemy but you must prioritize NPCs and Mercenaries with purple or gold portrait boxes, as well as ship-related skills. You can see these details through the eyes of Ikaros. You can have up to four lieutenants and their skill effects will stack together. These lieutenants can also board the ship along with you and provide the necessary covering fire or melee attack.
From the last mission, you may get spotted by more powerful ships that you can’t defeat yet. You’ll have no choice but to run away so row hard then enter travel speed towards your next destination.
Once you’re near the island Barnabas was talking about, slow down approach the docking area. Dock the ship when prompted then call Ikaros to scout the area. The target should be standing on the wooden platform, serving as a lookout in the area.
Approach the target and sneak behind him to knock him out. This is non-lethal move is required to recruit targets. Alternatively, you can use the Spartan Kick ability when they’re low HP to knock them out. Beware that while Spartan Kick’s damage doesn’t finish off targets, other factors like fall damage, drowning, fire, etc can still finish them off. Once they’re out, press R3 to wake them up and recruit them.
While here, you can eliminate all pirates in the area and loot the treasure box to complete the discovery of the island. Return to the ship to complete the quest. Your next destination is the Megaris.
The Ship menu will also be added to your main menu, allowing you to manage your ship and crew upgrades, as well as selecting the active lieutenants.