I've found ChatGPT to be pretty useful for generating ideas for adventure/campaign planning. Here's the question I asked it, feeding in details I took from canon sources as well as a few personal additions (Dreygu and Kahnebor are from "Domains of Dread: Sunderheart, the Funeral City"):

In the Eberron Campaign Setting, there is a magical city-state hidden in Droaam called the Venomous Demesne. It is ruled by four families of tiefling warlocks and wizards, the "Venom Lords," who wield powerful magic and craft dark wonders. To most outsiders, their traditions seem arbitrary and cruel. The price of magic is often paid for in pain and blood. Duels are an important part of their culture—never to the death, but always with a painful cost for the loser. The mages of the Venomous Demesne are brilliant, and over the last century have even begun to dig deeper into the mysteries of the Astral Sea.

Two of the four ruling families of the Council of Four are named Dreygu and Kahnebor. Please help me invent details about these houses, and the remaining two. What makes each of the four houses unique? Which house does Lord Bal Molesh, leader of the Venom Lords, belong to?

And here's what ChatGPT said:

Certainly! Let's create details for the four ruling families of the Council of Four in the Venomous Demesne:

1. House Dreygu is known for its mastery of infernal contracts and dark pacts. They have an uncanny ability to forge agreements with powerful extraplanar beings and demons, often trading in souls and forbidden knowledge. Dreygu warlocks are charismatic negotiators, adept at bending others to their will through charm and deception. They also possess a unique talent for binding outsiders to their service, harnessing their arcane abilities to enhance their own powers. The family's estate in the Venomous Demesne is a sprawling labyrinth filled with hidden chambers and wards protecting their prized infernal contracts.
2. House Kahnebor specializes in elemental magic and has a deep connection with the forces of nature. They are known for their control over the elements and the ability to summon and command powerful elemental creatures. Kahnebor wizards are often seen as guardians of the natural world, but their methods can be ruthless, seeking to dominate and harness the raw power of the elements. Their estate is built upon a series of floating islands in the Demesne, each one representing a different element, and visitors must navigate these unstable platforms to reach the heart of their domain.
3. House Vralkul is steeped in necromantic arts and shadow magic. They revere death and view it as a source of power rather than something to be feared. The Vralkul family has mastered the art of manipulating shadows and the undead, raising powerful wraiths and specters to serve them. Their dark spells are feared even among other tieflings, and they are known for creating deadly traps within their estate, guarded by undead sentinels. The Vralkul family's home is a grand, eerie mansion enveloped in perpetual twilight, with spectral guardians patrolling its grounds.
4. House Zaelora is known for their expertise in mind-altering magic and illusions. They are skilled at manipulating perceptions, creating illusions so convincing that they can alter the reality of those who fall under their influence. Zaelora enchanters are masters of subtle manipulation and are often involved in espionage and covert operations. They have developed secret chambers and passages within their estate, making it difficult for outsiders to navigate without succumbing to their enchantments. The family's domain is a multi-layered fortress of illusions, with shifting walls and deceptive architecture.

As for Lord Bal Molesh, the leader of the Venom Lords, he belongs to House Vralkul. He is a powerful necromancer and has a commanding presence in the Demesne. Lord Molesh has, over the years, perfected the art of raising and controlling undead, and his family's mastery of death magic has granted him a strong grip on power within the council. His residence, the Vralkul mansion, serves as the central seat of the Council of Four, where the ruling families convene to make decisions that shape the future of the Venomous Demesne.

I had some thoughts about its choices of words, like "Kahnebor wizards are often seen as guardians of the natural world"... absolutely not lol. Also, "Vralkul" is a bit too close to the nearby city of "Vralkek" for my liking. But I like the idea of the four houses having specialties in infernal contracts, elemental binding, necromancy, and illusions. I also like that it independently decided these four houses have complicated, labyrinthine, booby-trapped estates; sounds perfect for a cultural tradition that originated in Ohr Kaluun with its war mazes.