Here is the full list of all 18 A Timely Intervention achievements.
Artifact Defeated
6+ Sidequests Completed
All Along the Watchtower
A Timely Intervention
Secret Passage Found
Underworld Demon Defeated
5000+ gold
Frost Dragon Defeated
1000+ gold
Orc Leader Defeated
Hydra Defeated
Troll Defeated
Ancient Crypt Found
Borehole Worm Defeated
Argmahn Defeated
All Stonebarrow Lake Foes Killed
25+ Secret Rooms Found
12+ Sidequest Completed