Moe Chronicle

The H monster book gets filled in as you encounter different creatures in the dungeons. This trophy unlocks when it is 100% complete. Playing through the game normally should get you all the monsters somewhere on the Gothgal Quartz Area 7F Sealed Floor, but if you're missing one or two, check the H monster guide at the inn for the monsters with a similar level, then revisit that area and wander around until you encounter the missing monster.