Mission 9 - The Second Acolyte | Memorials and Soldier Diaries - First pass Castlevania: LoS 2 Guide

#22 Memorial

The guard you must use your Bat Swarf is right in the middle of the screenshot.

Use your Bat Swarm on one of the patrolling guards (the one standing further away from you) to distract him and the one that will arrive to help him, allowing you to get past them to the other side of the room - to get there you can possess the other guard or use Mist to slip near them undetected. After reaching the other side, stand above the grid without the airflow (closest to the elevator) and use your Mist power again to get to the lower level. You will get into a room with a Memorial