Here is the full list of all 15 Scelestum achievements.
Completed the tidal island on inquisitor difficulty.
Completed the tidal island on investigator difficulty.
Completed the tidal island on apprentice difficulty.
Completed the wizard's maze on inquisitor difficulty
Completed the wizard's maze on apprentice difficulty
Completed the island map on inquisitor difficulty
Completed the island map on investigator difficulty
Completed the island map on apprentice difficulty
Completed the crater village on inquisitor difficulty
Completed the crater village on investigator difficulty
Completed the crater village on apprentice difficulty
Completed the small farm on inquisitor difficulty
Completed the small farm on investigator difficulty
Completed the small farm on apprentice difficulty