There are 13 unique legacy titles associated with the Companions content.
Arcann's Admirer is obtained from completing "Date Night: Sparring Practice" achievement.
Combat Designation: L3-E7 is obtained from completing "Combat Protocols" achievement.
Comfort Enthusiast is obtained from completing "The Power of Comfort" achievement.
Geared for Combat is obtained from completing "Voiding the Warranties" achievement.
Imperial Squad Commander is obtained from completing "All For the Empire!" achievement.
Imperial Squad Leader is obtained from completing "For the Empire!" achievement.
Jorgan's Joy is obtained from completing "Trooper Precision" achievement.
Koth's Kindred is obtained from completing "Date Night: Planting New Roots" achievement.
Lana's Lover is obtained from completing "Date Night: A Worthy Opponent" achievement.
Republic Squad Commander is obtained from completing "All For the Republic!" achievement.
Republic Squad Leader is obtained from completing "For the Republic!" achievement.
Theron's Treasure is obtained from completing "Date Night: Romancing the Spy" achievement.
Vette's Vow is obtained from completing "The Makeb Heist" achievement.