Here is the full list of all 5 Mythrel achievements.
The base game contains 4 achievements, and there is 1 DLC pack containing 1 achievements.
Enter The Realm of Mythrel! Achieved by creating a Mythrel account!
Level 5, Achieved by winning fifty times in Origin realm matches!
Level 10, Achieved by winning one hundred times in Origin realm matches!
Level 20, Achieved by winning two hundred times in Origin realm matches!
Achieve obtaining over 1,000 Dragon Scales