This is a Dragon Quest VI crossover only using elements relevant to the Mirror of Ra

The Mirror of Ra is an Ancient Enchanted Mirror that has the power to Dispel Illusions and Curses and reveals the true form of objects including ponies. For example if the Mirror is pointed at a Changeling disguised as a Pony the mirror removes the illusion and the Changeling is revealed

Daring Do attempts to retreieve the Mirror from the MirrorMoor tower, but she did not know the tower is infested with deadly monsters. The most most deadly in this tower are the Ghost shadows and the Haunted Mirrors.

Why are they deadly? [The Shadows cannot be hit physically magic harms them, and they can blow ice from their mouths and the Mirrors can copy others they reflect in their mirrors and even copy his/her skills