Blox Fruits Marine Fortress Flagpole Secret Guide (Parlus, Sea 1)

Marine Fortress hides one of the easier Island Secrets added to the First Sea in Update 30, and it does not involve a boss or a puzzle. You talk to an NPC in a tower, find a coil of rope lying on the ground, and stand still on the flagpole platform while the fortress cannons try to knock you off it.

Quick answer: Speak to Parlus in a Marine Fortress tower and pick “What’s with the empty flagpole?” then “I’ll raise your flag”, collect the rope from under the small wooden shelter near the water, then stand inside the glowing ring at the base of the central flagpole until the flag reaches the top and return to Parlus for your reward.

Marine Fortress flagpole secret: key details

Detail	Value
Location	Marine Fortress, First Sea
Quest giver	Parlus, inside one of the four corner guard towers
Required item	Rope, found on the ground under a wooden shelter near the water
Objective	Stand on the central flagpole platform until the flag is fully raised
Main hazard	Cannon fire aimed at the flagpole platform
Reward	EXP and Secret Levels, claimed by talking to Parlus again

Note: the tower NPC’s in-game label is easy to misread, so you may see the name written as Parius. It is the same character who sells the Black Cape for $50,000 from a Marine Fortress tower, which makes him simple to identify if you have shopped there before.

How to complete the flagpole secret

Travel to Marine Fortress and get up into the guard towers at the corners of the crescent-shaped fortress. Parlus stands inside one of them, and a green interaction marker appears above him once you are close enough.

Green interaction marker floating above the tower NPC at Marine Fortress — The green marker above Parlus is your cue that you are in range to open the dialogue. Image: Gamer Robot

Open the dialogue and choose “What’s with the empty flagpole?” to hear him out. Follow it with “I’ll raise your flag” to accept the task, which is the point the secret actually starts tracking.

Head back down toward the water and look for a small wooden shelter near the docks. The rope is stashed on the ground underneath it, and you pick it up by walking over it rather than pressing an interact key.

On-screen objective text telling the player to find the stashed rope and reach the flagpole — The objective text tracks two things at once, the stashed rope and the flagpole you need to bring it to. Image: Gamer Robot

With the rope collected, make your way back to the central flagpole in the middle of the fortress. The objective text updates the moment the rope is in your inventory, pointing you toward the pole.

Player crossing the fortress grounds toward the central flagpole after picking up the rope — Crossing the fortress grounds back to the central flagpole once the rope is in hand. Image: Gamer Robot

Step onto the circular platform at the base of the pole, inside the glowing ring, and stay there. The flag climbs on a timer while cannons fire at the platform, so dodge in place and keep at least part of yourself inside the ring until the flag reaches the top.

Side-by-side of the flagpole capture ring, quiet on the left and taking cannon fire on the right — Left: the capture ring while the flag climbs undisturbed. Right: the same ring once the fortress cannons open up on it. Image: Gamer Robot

When the flag is fully raised, a prompt sends you back to Parlus. Fly or climb up to his tower and talk to him a second time to close out the secret.

How to confirm the secret is complete

Two things tell you it worked. First, the flag sits at the top of the pole and an on-screen message points you back toward Parlus instead of leaving the objective text on the flagpole. Second, the reward only lands after that final conversation, so you should see EXP awarded and Secret Levels credited when the dialogue ends.

If you walk away right after the flag goes up, the secret sits unfinished. Nothing is lost, but it will not count until you return to the tower.

Why the flag stops rising

You stepped off the circular platform. The flag only climbs while you are holding the ring, so chasing enemies or repositioning too far pauses it.
You died to cannon fire. Marine Fortress quests are tuned for levels 120 to 150, and the cannons hit hard enough to end a run if you stand still and tank every shot.
You interacted with the flagpole without the rope. The pole does nothing until the rope is in your inventory.

What the Secret Levels count toward

Island Secrets are the Update 30 progression layer for the reworked First Sea, with 40 of them spread across the sea’s 16 islands. Each one you finish awards a star alongside its rewards, and collecting all 40 stars unlocks the Teleporter in Middle Town.

The Secret Levels handed out at the end feed the new level system, which is what lets you push past the old cap. The flagpole task is one of the cheapest entries on that list, so it is worth clearing early while you are already grinding Marine Fortress for EXP.