Here is the full list of all 40 Soulblight achievements.
Choose the Superstitious Path
Choose the Stubborn Path
Choose the Impatient Path
Choose the Slothful Path
Choose the Fierce Path
Choose the Unquenchable Path
Choose the Unyielding Path
Convince Yarlo to venture into the Sanctuary himself
Choose the Gluttonous Path
Help Brothr learn the secret of the Ancient machinery
Choose the Sadistic Path
Choose the Thievish Path
Choose the Abusive Path
Choose the Conniving Path
Choose the Hypochondriac Path
Bring all the punch cards back to Quara
Choose the Playing God Path
Choose the Paranoid Path
Choose the Greedy Path
Defeat the boss at the end of the Observer's path
Choose the Slithery Path
Choose the Prying Path
See the "good" ending of the game
Finish the game without using any Taints
Learn why Cecil is so eager to give you store discounts
Choose the Soulless Path
Choose the Fanatical Path
Choose the Vengeful Path
Defeat the boss at the end of the Devotee's path
Choose the Uppity Path
Choose the Cowardly Path
See the "bad" ending of the game
Receive a candle from Albern... a wax candle of course
Choose the Cannibalistic Path
Choose the Bloodthirsty Path
Choose the Obsessed Path
Defeat the boss at the end of the Zealot's path
Choose the Acquisitive Path
Choose the Reckless Path