Stellar Blade

Upon returning to Xion and speaking to Lily after the “Alpha Signal” main mission, before you head to the Great Desert, you'll unlock the special Tachy Mode, where you can turbo charge yourself using and for a short amount of time.

One bit of advice we would offer is to invest in the left-hand tree of the Tachy Mode skill tree, and then go up. This will lead you to the Judgement Time ability, which reduces Tachy Energy consumption and gives you longer to deal damage before the effect wears off.

To get the ‘Reavenging Agent’ trophy, you just need to then kill 50 enemies using it. Like the ranged weapons, we didn't tend to use this a lot, so if you want to boost this one, find a large group of Creepers in the southwestern Wasteland and use it on them. Rest at the camp, rinse and repeat.

Easy peasy, really.