The Templar hunt side-missions become available after clearing "Sequence 4: This Old Cove". They are all marked in the open world map and has 4 memory sequences each. Finishing each will reward you a Templar Key. Earn all 5 Templar Keys to unlock the Templar Armor located in the mansion at Great Inagua. Collecting at least 4 keys key also give you the achievement "Help a Brother Out".
* Mission Name: The Taino Assassin
* Mission Area: Cayman Sound
You have to beat Opia Apito by getting more pelts than she does within the time limit. Head over to the green zones in the map to find prey. Use eagle vision within the zones to locate and tag the animals. Just shoot the animals from far away, then skin them afterwards. Get 2 to 3 more skins, then you will be ambushed by a white jaguar next. Follow the onscreen QTE prompts to shake it off, then shoot it using your firearm when it runs away.
* Mission Name: Templar Ships
* Mission Area: Grand Cayman
Fast travel to Grand Cayman first. Look for Opia in the docks. Talk to her here. Keep following her along the way. A green marker appears then. Go over the marker and head to the green zone on the map. Turn on eagle vision to tag your target. Follow the group and eavesdrop on them along the path. Blend with civilians when they stop and look around to avoid being seen. After they split up, steal from the guy with the orange marker.
* Mission Name: Right-hand Man
* Mission Area: Grand Cayman
Head again to Grand Cayman for the mission and follow Opia Apito. Hide into the palm stack when you are advised to. Chase after the running target first until he reaches the docks. Board the Jackdaw immediately and chase the target. Hit the fire barrels that they leave behind. Just destroy the enemy ship now, board it, then kill the target.
* Mission Name: The Trail of Lucia Marquez
* Mission Area: Pinos Isle
Travel to the Pinos Isle. Locate Opia at the southwestern area of the map. Talk to her as usual. Follow the target down until you reach another ruins area. Once you are tasked to kill the target, shoot powder kegs to eliminate his minions first. Repeat this for the second wave of enemy reinforcements. Now, chase after the target and assassinate her.