Here is the full list of all 18 Thorne - there are Son of Slaves (Ep.2) achievements.
Old Lovers
No Men Left Behind
Troll Killer
Hero
Old Friends
Rescuing Matthias Again
Horse Racer
Rezier's Immortality
Quilyn's Whispers
Tomb Raider
Fu***ng Badass
Self Control
Deathlips's Nostalgia
Die, die baby
Son of Slaves
Duke's Insurance
Ring in the Swamp
Among the Stones