You must have already completed this tutorial as a prerequisite: Modifying a 3D Model's Geometry
Bloodstained uses something most Unreal Engine games don't: Mirror Tables. If you don't generate a Mirror Table when editing any character/enemy in the game, the animations will break when the character is facing left. This tutorial will cover safely editing Miriam's body, the techniques will apply to any other character in the game.
This tutorial uses the following tools:
Pick a 3D modelling software, such as:
Miriam's body is modified, and the mirroring still works properly.