Princess Ezam is the younger sister of Lord Byrinth. She was killed off before the events of Super Mario Mazes at the hands of her own brother.
Princess Ezam and Lord Byrinth were the rulers of their kingdom across the sea. However, neither could decide on a proper way to rule, Ezam wanted to rule with kindness, while Byrinth wanted to rule through fear and tyranny. Leading to their kingdom being split in half, one half controlled by Ezam and the other controlled by Byrinth.
After searching through the ancient texts of Mushroom Lore, Byrinth found that the power of the Shadow Cube can grant the holder unbelievable power. Byrinth searches in the Stone Mountains and finds the Shadow Cube. Upon touching it, Byrinth lost most of his skin, leaving him a skeletal monster. Corrupted by the Cube's power, Byrinth returned to his kingdom and successfully murdered his sister, gaining complete control of his kingdom.
Princess Ezam later reappears at the end of the game, granting Mario the power to destroy Lord Byrinth and the Shadow Cube.