"A Spanish expedition is looking for a lost artifact on this island. The leader of the group is a Templar financier. Kill him before he finds this artifact."
You must travel to Abaco Island to complete this contract. Fast Travel to the viewpoint found there to get started easily. Turn to the South and look at the tent. You will see your target go into it. Enough of him will remain visible for you to tag him with a Berserk Dart. After that just perform a Leap of Faith into the hiding spot and wait out the commotion.