Unity Kincaid was born during the first decade of the 20th century. In 1916, Dream of the Endless was imprisoned by Roderick Burgess, and people all across the world were suddenly afflicted by a inexplicable "sleeping disease". Unity was among them, the victims slept almost constantly, they could not wake up before the Dream Lord was freed, almost 80 years later.
After Dream's escape from Burgess, the victims of sleepy sickness awoke, unaware that their lives had passed them by.
Unity had been fated to be a "vortex of Dream," a unique entity that appears only rarely, with the ability to connect the dreams of other beings, a dangerous ability that can cause the destruction of The Dreaming. As such, the only time Dream is allowed to take a human life, is to kill a vortex. Both Dream's captivity and Desire's interference, however, confuse the issue, and eventually Unity's granddaughter, Rose Walker, becomes the vortex.
Before Dream can kill Rose, however, an elderly Unity appears in the Dreaming, explaining that she should have been the vortex. She asks Rose for her heart, and Rose pulls a red glass heart out. Unity takes the heart and breaks it, killing herself, and ending what would have been a catastrophe for both Dream and the Dreaming.
* Desire's motivation for raping the helpless Unity was that as the sleeping woman could not fulfill her role as vortex, a descendant would inevitably have to fill the role, and Dream would then be forced to kill a member of his own family in order to destroy the vortex, thus bringing the vengeance of the Furies on himself.