I have looked into the void of space, and into the void of her eyes, and of the two, hers was the colder.
Circumstance of Birth
Though she was born in the Marianiyan Territories, Brood's true cradle is considered to be Laughters' Bade—a gore well in which she was tortured, killed, and resurrected multiple simes by Kyzanic Psiolic who were trying to perfect the art of raising the dead without destroying their memories.
Their experiments were not a total success, but were success enough for her to remember the evil they had done, and to exact back upon them in spade.
Their treatment of her became a lesson by which she lived. She was a notoriously, insidiously cruel character, who believed that torture and pain were the only true path to empathy with a fellow individual.
From wildling to weapon
After her birth in Laughters' Bade, Brood (though she was known at the time by another name, Lunathea) earned herself a reputation among the wilds of the Territories as a rampant witch who would kill those who crossed her paths.
This was not particularly standout for the region, but when she began to kill Sathiid nobility and House Nchraementho Psiolic with as much ease, she began to garner attention.
At height of power, in which she had amassed a platoon of undead and built a lair for herself from the ruins of the Marianiyan Madlands, she was approach by Lady Undyr'rh of the Nchraementho. The Lady offered to personally train her, in return for her servitude.
Brood agreed, and her training began. She became versed in the Psiolic arts, at which she quickly became proficient. She learned to cut down scores of trees with a sweep of her hand, to peel flesh from bone and to boil blood in its veins. Her mastery of Kyzanry grew along with, and her ability to raise skeletons and bodies from the dead exponentially increased. What would've taken her a week before she could do in a night now, and though she took her skills for granted and was focused in her studies, the Lady began to fear her capabilities.
On her own, Brood trained herself. She infected herself with Sathiidism, she embraced its hunger, and did not fear risk of it killing her, because she knew the feeling of death, and she knew the road back to life.
She had nothing to fear.
But the Lady did. Rightly so. In her fear of Brood she tried to restrain her power, but Brood saw through her devices and turned on her.
Lunathea adopted her famous title, written in the blood and the marrow of a slain lady Undyr'rh. She became Lady Brood Blood-Kyn of the Nchraementho, with all of the rights and powers that gave.
Rise to Power
How can you claim to understand the sorrows of this world, if you have never experienced them. No untested mettle can be called good, only benign. It is when we are destroyed and cut to the bone that we reveal who we truly are, what we are truly worth.Brood Blood-Kyn
Later on in her life, after taking over House Nchraementho, Brood gathered sympathetic, powerful minds and entities, banding them together to bring down the majesty and monoliths of Jhoutai and, to a lesser extent, Eden. This cabal called itself The Harrowing, and quickly began to cut a path of destruction through the Pre-Banner Pantheon of Monoliths and the nobility of the countries which ruled the world.
You sit in high thrones, you lay in gold beds. You claim to care for the sorrows and plights of your people, when you yourself have known no sorrow. It is time to usher in an era of wisdom, of empathy, and of sobriety, and to do that, we must first remove the crown of our tyranny at its shoulders.
Her allies in the Harrowing—Immundus, Crescendo, and several others—each took a country or region under their belt. She chose Aempis, and was quite nearly successful at killing Emporer Clasnithra Illithra Khandea ere it not for the intervention of the Engine of Entertainment, Anthem.
Anthem's Thrum Negated Brood's power, driving her back, and weakening her, before the Monoliths of Aempis, lead by Emperor Khandea, were able to finish her off.
It is uncertain if Brood is entirely gone. Myths abound suggest that she lived on in some form, either as leftover secrets and magics from her birth in Laughters' Bade—a cradle of viscera which gave her the ability to return even from being reduced to gore—or by even stranger tales...
The Thrumming song of Anthem rang out, each note a gorgeous color in a prism sound, each beat a blow to the monster Brood had become in her final hour. The high notes cut like blades, the low notes broke her bones—yet the beast would not give up.
Heard by few, retold by fewer, and comprehended by only one, a single fell note was sang—not by Brood, but by something else, something both of Brood and of Anthem, a Dirge.
Between them something else was made, and I know it must lurk in the stars to this day, fulfilling the final drive of Brood.
It is far more terrible, and insidious than she could ever strive to be.