01 - The Forts | Sequence 5 AC IV: Black Flag Guide

First, take care of the ship

Before you start this mission, make sure that you are in the possession of mortars, and buy more if necessary. The objective is to seize the fort which is additionally guarded by a brig. First, deal with the enemy ship, best by swimming out of the range of the fort mortars (around 550 meters). If you have been hit, after you seize the ship, use it to repair possible damage.

Use the mortar to destroy the towers

OPTIONAL OBJECTIVE- use the mortar to damage the fort

Once you have dealt with the ship, it is time to turn to the fort itself. The best method is to use the mortar for that. Not only because of the bonus objective. The mortar is, arguably, the most formidable naval weapon. Additionally, while targeting the fort, you can be sure that you hit it, because it will not sail away, unlike the enemy ship. The mortar is activated with the left bumper. Aim at the enemy towers and pound at them until you destroy them. For the whole time, you need to watch out for the enemy fire from the fort. Remember to keep an eye on the color of the water. The best strategy is to sail fast, to the side and go in crescents in front of the fort. Also, at closer distances, the heavy shot, plus a shot into the weak point, will be very effective. Once you have destroyed both towers, start running towards the fort.

Use a running assassinate to kill the officer

OPTIONAL OBJECTIVE- use a running assassinate to kill the officer

Once inside the fort, ignore all the fights and focus directly on the officer that you need to kill. Kill him by surprise by running into him. If he realizes that you are around, escape to lose him and try again. After you kill the officer, the remaining soldiers will give up. Use this to search the chests and the Animus fragments in the fort. Once you are ready, walk inside the keep to complete this mission.