Here is the full list of all 18 Choice of the Pirate achievements.
Acquire two ships to launch your fleet.
Defeat the Lusca.
Fall under the curse of the ghost ship. Congratulations on your zombification!
Capture your first target without sinking it.
Acquire one ship to launch your fleet.
Remove the threat of Blackguard from your future.
Save Jim the Cabin Boy from an untimely death.
Acquire three ships to launch your fleet.
Earn the notice of El Sabio.
Turn over your first bounty to the Crown.
Convince Evan Lark to open up to you.
Become a spy for the Crown.
Defeat the ghost ship.
Steer the Crown in the wrong direction.
Steal from the Pirate King! You've got guts, Captain.
Rescue a mermaid.
Will those mutineers get what's coming to them?
Become the Pirate King.