The Last Remnant

You need to use Timeshift 100 times to unlock this achievement. You should unlock it during the course of the story. You can grind it by simply standing still, activating it, letting it run out and refill, then repeating.

You'll unlock the Timeshift power the first time you go to Dillmoor at the start of the game.

Whilst this achievement isn't directly plot related you will earn it simply by playing through the game. However it can also be easily boosted.

At any point after you unlock the ability to use Timeshift press RB to activate it and then immediatley pull RT to end it. This is best done when out of range of any monsters so that the battles don't slow you down. The reason for pulling RT is so that you don't have to completely deplete your TImeshift metre and as such only have to wait for it to recharge before you can use it again.