This trophy is titled "Exorcist" and it requires you to defeat a demon.
This is a story based trophy and is unmissable.
Inside the Regal Apartments, when attempting to go up to the third floor, a cutscene will play which will introduce demons to Ronan. Follow the on-screen prompts about how to hide from them. Leave the hiding spot and hold down R1 to see the demon through the walls. Approach it from behind via the closest where the ghost was and then the game will prompt you about demon executions. Hold down R2 and after a couple of seconds, a prompt will appear on-screen. While still holding down R2, perform the on-screen prompt to kill the demon and unlock the trophy.