Blaze Empress

The Blaze Empress is a strict and strong leader, having been described by Philza as a "total badass". Her place of residence is the Quartress, a giant fortress of quartz located at the center of the Nether Void, and she is presumably a member of an unnamed group of five godlike entities.

By the Empress' side stood He and She, her lead commanding soldiers, and well as Sandy.

Lore
The Empress is very old, and has therefore had a long time to master her skills and magic, becoming incredibly powerful.

She had a pet sheep, dyed red, called Enemy which lives next to her throne in the Nether Void (a reference to the blue sheep, Friend, which Ghostbur owned on the Dream SMP).

She also has two guards dubbed "He" and "She" after two faces made in the lava outside of the Nether Void's bounds. They reside on either side of the Blaze Empresses throne. Further down stands Sandy.

Relations with the Ender King
The Blaze Empress and the Ender King were enemies, their realms at war.

Relations with the Ocean Overlord
"'The Blaze Empress didn't care about the Ocean Overlord.' - Philza Minecraft"

Fanon Interpretations
Interpretation of the Blaze Empress by @chewwypepsicola