Here is the full list of all 30 Mortal Sin achievements.
Complete Path of Absolution 5
Complete Cave C on Path of Torment difficulty
Complete the Trial of Resolve on Path of Torment difficulty
Complete Forest C on Path of Torment difficulty
Complete the Maw of Sin on Path of Torment difficulty
Complete Dungeon C on Path of Torment difficulty
Complete Forest B on Path of Torment difficulty
Complete Cave A on Path of Torment difficulty
Complete Dungeon B on Path of Torment difficulty
Complete Forest A on Path of Torment difficulty
Complete Cave B on Path of Torment difficulty
Complete Dungeon A on Path of Torment difficulty
Complete the Trial of Resolve
Complete Forest C
Complete the Maw of Sin
Complete Cave C
Complete Forest B
Complete Dungeon C
Complete Cave B
Complete Forest A
Complete Dungeon B
Complete Cave A
Complete Dungeon A
Complete Path of Absolution 10
Complete Path of Absolution 15
Complete Path of Absolution 20
Complete Path of Torment 5
Complete Path of Torment 10
Complete Path of Torment 15
Complete Path of Torment 20