Aragami

Before you can earn this trophy, you'll first need to unlock the 'Ledge Kill' Shadow Technique. Once you've unlocked this, point your 'Shadow Leap' (teleport) technique at a dark spot on a ledge below an enemy - you should see the icon change appropriately and the teleport marker will become red - and release. You'll then pull off a 'ledge kill' and earn this trophy.

Here's a video guide, courtesy of Trophy Germany: