Load Chapter "The Keep" from Episode 3, directly at the starting Point you can see the 3 Ravens. Use your Focus Time to kill all 3 in one Try. Shoot as first the middle Raven, then the left and as last, the right raven. Currently you can reload the Checkpoint and kill another Raven to earn this Achievement but i personal think this is a Bug und will be patched in the Future.
thanks Nesmaster (i have transform only all in one Solution & Video, credit to him!)