Here is the full list of all 14 Deitydead:Elder Trial achievements.
Complete Novice Mode
Conquer the Forest Trial
Triumph in the Desert Trial
Overcome the Tundra Trial
Conquer the River Trial
Complete the Cave Trial
Finish the Relic Trial
Successfully Complete the Ultimate Trial
Conquer the Desert Trial on Hard Mode
Master the Tundra Trial on Hard Mode
Triumph in the River Trial on Hard Mode
Overcome the Cave Trial on Hard Mode
Successfully Navigate the Relic Trial on Hard Mode
Achieve Victory in the Ultimate Trial on Hard Mode