Ponce de Leon is one of the main antagonists of Rogue Legacy and the Boss monster required to beat the Tower, a non-optional area required in order to gain access to the final boss (and true antagonist).
Ponce de Leon is a living ball of malevolent fire and will constantly chase the hero around the room.
While moving, he will periodically leave a large flame in his wake - this will remain for about the time it take for him to do a lap around the perimeter of the room.
He will also occasionally pause, glow, and then move at the hero at an accelerated rate - several of these can be done in a row.
In addition there are several Spiketors throughout the room that act as an additional hazard.