Here is the full list of all 11 Edge of Twilight Return To Glory achievements.
Kill 5 Tainted in less than 5 minutes
What next for Lex?
Kill every Tainted
Kill a Jiankra in less than 10 minutes
Kill 3 consecutive Tainted whilst using Ether Fury
Perform 50 Finishing Moves
Find 5 Lithern artifacts
Research every book in the Library
You've got a nose for the hunt
Kill 10 Valmin in less than 60 seconds
Kill 10 Wolthern in less than 10 minutes