Kaza was a member of the Liaforan royal family who attempted to visit Akinah in Aimia, on the First Dreams (with a crew of sailors), seeking a cure for her Soulcasting savantism and to uncover the secrets therein.
After the entire crew and Kaza were poisoned by the cook (who described Kaza as being barely human), Kaza slowly gave in to the desire of smoke transcendence while Soulcasting - rather than dying by poison - though she resisted its affects much longer than everyone else on the ship.
Kaza was, slowly, becoming smoke.
... her hair, her ears, and now parts of her face were disintegrating. There was a hole in her cheek through which you could see her jaw and teeth. Lines of smoke rimmed the hole; the flesh seemed to be burning away. Air passed through it when she spoke, altering her voice, and she had to tip her head all the way back to drink anything. Even then, it dribbled out.
Kaza's condition caused her to lose familiarity with some aspects of human behavior. When the sailor Droz spoke to her, she had to consciously remind herself just why someone might do such a thing.
She had an independent streak and long felt controlled by the royal family. She made her trip to Akinah in defiance of them, and resented the way they had essentially imprisoned her to maintain control of the Soulcaster in her possession. She made it clear to Captain Vazrmeb that while she was willing to help him, she was not a thing to be used.
Kaza was intimately familiar with the use of a Soulcaster which produced smoke. She was able to Soulcast partial objects - which is more difficult than Soulcasting entire objects. She could partially see into the Cognitive Realm, which included spren themselves.
Kaza was a cousin to the prince of Liafor and had been assigned at a young age to use a royal Soulcaster, a magical object which was to be kept always within the royal family. Over many years, she grew extremely attached to the Soulcaster, used it to excess, and therefore became a Soulcasting savant.
She was hired by Captain Vazrmeb to help him navigate to Akinah, which seemingly furthered her own goal of curing her savantism. In effort to reach the island, she partially Soulcast away the rock barriers around it. Although she made it from the First Dreams onto land after the poisoning by the cook of all aboard (unlike the captain and crew), Kaza Soulcast the ground around her into smoke, finally giving in to the urge to include her own body in a Soulcasting, so that she could determine her own destiny ... rather than dying of poison and allowing the cook to take her Soulcaster from her.