"Kill 8 guards by destroying powder barrels" is an optional mission objective in Sequence 12 / Memory 02: Royal Misfortune
Walkthrough[edit]
Run and dive off the bow of the jackdaw. You need to find Roberts in Principe and he is not going to make that easy. Swim over to the to the to the rocks to the left of the tree hanging over the water. Duck into the Stalking Zone and look around for the Powder Kegs. Engage the first group of soldiers that you find. Use your guns a little, but be sure you have at least 1 shot left. This will draw a large group of Soldiers in toward you. When they are closing, shoot the Gunpowder barrels to just take out the whole group.
If this needs to be repeated, head to the Watch Tower to the East along the coast. The usage of Berserk Darts is highly recommended as well.
