The Fire Wheel is fairly self-explanatory. It's composed of an inner and outer wheel connected by four spokes and sporting a cyclopic, tusked face.
The Fire Wheel's primary attack is to barrel towards the Master and bash him with the fiend's fiery body. It can move horizontally and vertically, so jumping on the upper platforms does not equal safety. As a secondary attack, the wheel will float to the middle of the room and spew green projectiles around it.
The Master must constantly be on the move in order to avoid taking too much damage, as it can really stack up in this fight. Magical Stardust is surprisingly very effective here; even on the ground with the platforms above to shield it, the Fire Wheel can take massive damage from the spell.
The Fire Wheel bears a resemblance to Buer, the Great President of Hell.