There is no one-size-fits-all answer to this question, as the best strategy for beating Moreau will depend on the player's individual character and playing style. However, some tips that may be useful include:
1. Shoot the boss when its mouth is open - When in its regular form, Moreau will attack with a wide AOE, so it is important to stay away from the boss when its mouth is open. Shooting the body when the boss is in this form will deal huge damage and should be your main focus when fighting it.
2. Use area-of-effect abilities - A large number of area-of-effect abilities can easily take down Moreau, so try to use them whenever possible. These abilities will damage the boss even if you're not close to it, which makes them very effective against this enemy.
3. Build up your fire resistance - Moreau fires harmful fireballs that can deal a lot of damage