Strength of the Sword 3

It is best to attempt this trophy on the Goblin Scouts, as they are the weakest enemies in the game. You will likely earn this trophy naturally during normal gameplay. If you don't, however, then just load up a level that has a Goblin Scout in it (such as level 1 or wave 1 of the Challenge Pit on Easy difficulty) and use the Lightning Storm attack on him. It should kill him instantly. You can really use any ability you want for this as they will all kill the Goblin Scout within seconds, without ever giving him a chance to move. If done right you'll get a notification at the bottom of the screen that reads "DEVASTATING".