Pharaoh appears as a gigantic death mask used in burial rites, made with gold and gilded with precious metals and paint.
Pharaoh's primary attack is to float above the Master's head; once directly above the Master, Pharaoh will drop, trying to crush the deity. After it hits, it fires a shining magic projectile that will cause damage. More importantly, the projectile, once it hits a wall on either side of the chamber, forms into an arrow-shooting mask, so the Master must dodge two missiles instead of one.
However, Pharaoh is a big target and is easily destroyed by sword strikes. Magical Stardust will take it out quickly. Since the Master can't move while casting, though, he makes an easy target for Pharaoh to drop on.