In this Secret Mission, you have three Shadows to kill. They will come at you either one at a time, or all at once. Which pattern you get is pretty much up to luck. Standard Shadow tactics still apply, but the close quarters may cramp your style. If you have Nightmare-β the small space might be a slight advantage with all the ricochet. If not, stock up on 5-6 holy waters, they will expose the shadows cores instantly for an easy win.