Fierna

In name, Lady Fierna ruled Phlegethos, commanding the fiery layer from her palace of rock and magma. In truth, her father, Belial, was the power behind the throne.

Combat
Unlike her father, Fierna never relies on a weapon. Instead preferring to use her mastery over flames to manifest a flame blade and fire shield.

Cult
Being a newer archdevil in the Nine Hells, the cults that arose to venerate her struggled to settle on a specific agenda or method of operating. Their temples were often improvised whatever they could find. Clerics who worshiped her often did so through the domains of Evil, Fire, and Trickery. They were also well known for using scimitars in combat.

Relationships
Fierna is best friends with her fellow archdevil Glasya and would often spend time at her fortress in Malbolge. In imitation of her friend, Fierna eventually started to refer to herself as an "archduchess." She was also encouraged by Glasya to start building a network of devils and cultists separate from that of her father's forces, much to his chagrin.

Out of the several dukes that serve the domain of Phlegethos, Bathym and Zapan have pledged their loyalty to Fierna over her father.

Fierna once tried to court a mighty archfey, hoping to seduce them into relinquishing their soul. Her efforts ultimately went nowhere, but a group of the lord's satyrs became infatuated with her. Desiring some form of gain from her time spent on the lord, Fierna decided to corrupt the satyr with her infernal powers and transformed them into the creatures known as forlarren.

Discrepancy
Fierana first appeared in Dragon magazine 233, but the spelling of her name was later changed in the Book of Vile Darkness sourcebook to Fierna and that is how it has been written ever since.