Marine Fortress

Marine Fortress is the level 120-150 stop in the First Sea, picking up right after you've cleared the lower Jungle and Pirate Village stretch and pushing you toward the back half of Sea 1. As the name suggests, this is a heavily defended Marine HQ, so expect to be swarmed: Marine Lieutenants, Marine Captains, and the Chief Petty Officer all patrol here, giving you a dense cluster of enemies to grind XP efficiently without much travel. Two quest givers (the Chief Petty Officer and Marine Captain lines) keep a steady stream of objectives flowing. The real reason this island matters long-term, though, is the Bartilo quest — it starts here and is the gateway to unlocking Sea 2, so don't skip it. On the loot side, the Marine Coat and Slingshot are the notable pickups worth farming. Practical tip: pull groups in the open courtyards rather than chasing single NPCs, and once you clear the quests and grab the coat, take Bartilo's quest and start prepping for the jump to the Second Sea.