Here is the full list of all 22 Thorne - there are Death Merchants achievements.
Speak to Layla at Hollow Lake's bridge
Speak with the Death Merchant
Find the accessory near Simeone's Cave
Find out about Eldyn's suicide
Slay the Abyss Mermaid
Take the Lycan's contract
Karma is a...
Convince Skillet into releasing you
Take the blame for Idegert's murder
Slay the Wyverns at the Lighthouse
Find the Fallen King's Crown at Fire Isle
Defeat Ray at Gang's Hideout
Save Matthias from Ray's Gang
Face the Lycan at Hollow Lake
Meet McArthur at the Estate
Speak with Layla at Hollow Lake
Destroy the nests at the Goblin Cave
Defeat the Revenant
Find the Rowens near McArthur State
Bring Olav the antidote
Speak to Faida at Ocean View
Defeat Ray at Dead End