So, you've finished collecting all 16 of the Mayan Stelaes when you head back to Edward Kenway's Great Iguana hideout only to realize, "Oh, there's that Templar Outfit, too."
You will need to put some time in to get the keys, as they are guarded by Templars who won't go down without a fight. There are four Assassins you have to help before acquiring the keys, each with their own vendetta against a Templar.
Below is part one of the four part Templar Hunt missions' guide, courtesy of IGN. If you have any questions, leave us a note in the comments section below.
The order of the Templar Hunts doesn't necessarily matter, but I do suggest you start them after you've completed the main storyline. You want your Jackdaw fully upgraded for smooth sailing during these missions.
TEMPLAR HUNT: Opia Apito, The Taino Assassin
1. Finding Opia:
"First, find Opia Apito on Cayman Sound (327,334). First, you must prove yourself to her, so go out and hunt. Use Eagle Vision to find critters, then shoot them or make them fall asleep, and skin them. You need to keep up with Opia, but it isn't too hard. Look by the beaches, as there are more animals out there. After you get at least four animals, a white jaguar will spawn, and attack you. Kill him now to finish the mission."
2. Pickpocket the Templar:
"First, sail off to Grand Cayman (397,324) to get to Opia again. Follow her through the town while talking. Once finished, go find Alvin using Eagle Vision. Once located, eavesdrop on the Templar and his associates. Once their conversation is done, get behind one of them, and pickpocket the ledger from him."
3. Chasing Vargas:
"Talk to Opia again on Grand Cayman. Follow Opia again while she explains things. She will then tell you to hide, so turn around and dive into the pile of palm fronds. Now, chase and catch Vargas. He gets away, so hop behind the wheel of the Jackdaw, and incapacitate the ship he gets on. Board it, and take out 5 enemies, and you will have some face time with Vargas."
4. Take Down Lucia Marquez:
"Set sail for Pinos Isle (335,469) to find Opia for one last time. After talking to her, tail the soldier with her through the jungle. Move from stalking zone to stalking zone without being detected...Once you get to some ruins, take out all of the guards. Use the powder kegs on the ground or the stalking zones to clear the area. Once the area is clear, a second wave of enemies comes. Take these dudes out now. If you want to do this quickly, use smoke bombs. Once the second wave is done, chase after Lucia Marquez. Once close, take her out to get her Templar key."