The achievement is unlocked after you have killed 100 enemies with the "Total Clarity" not just used the skill on them. Chapter 3, choose to fight Ardyn.
Other FFXV Guides:
- How to Get The Royal Boat.
- How to Get a Chocobo.
- Grinding for Power.
- Costlemark's Cube Maze Helper.
- Max Out Every Skill (Cooking, Fishing, Photos, Survival).
Master of the Elements
The achievement is unlock after you have killed 100 enemies with the "Total Clarity" not just used the skill on them.
You can also complete this achievement in chapter 1 but I found it easiest in chapter 3 where you can one shot all of them and you don't have to run around to look for enemies, they will come to you.
Chapter 3, choose to fight Ardyn.
After you have made the choice to fight Ardyn at chapter 3, go back on the platform behind you and you will be safe from Ardyn.
He wont come after you and you can now wait here until his armies spawn. Use the Ice attack for AoE to make it quicker, you should be able to one shot all of them.
Kill, chill and repeat until you unlock your achievement.