Origins
As a child, Kesu had a fairly normal life in Wind Reach, working, laughing, and playing. She was a Yasi of a Chiet parentage, and she had planned her life on this fact. It all seemed to be coming together, until one day. The day she ran away from the others, because she was getting teased, over some trivial fact. On that same day, a pair of sociopaths roamed the valley below the mountain. They found Kesu, and at first, they seemed nice enough. Until she recovered.
Capture
The pair, a man and a woman, were self-proclaimed "scientists", and they were students of one of the most primal arts. Pain. They were obsessed with it, day and night inflicting tortures upon each other, and Kesu, and recording their reactions to it. They hid out in a cave, which they obscured thoroughly, making it appear that no one had disturbed it for years. And even if the hunting parties that roamed around the mountain had checked the inside, they wouldn't have found anything, for the duo had set up a 'laboratory' set into the roof of the cave, accessible only by a rope ladder. No noise would escape, for they gagged each other when they began the torture, and Kesu was too shell-shocked by the second season to cry out even when they weren't hurting her. For two seasons this went on, and severely traumatized Kesu, scarring her for life.
Rescue
The duo, a man and a woman, dragged Kesu along with them, as they inflicted various tortures and punishments on each other and Kesu. This reduced their travel speed, which allowed a young warrior, travelling on the road, to find them. The two invited the man to eat at their fire, and chained and gagged Kesu, still bleeding from the night's earlier 'experiments', just outside their encampment. The warrior suspected nothing, until he went to relieve himself outside the campsite, and found Kesu chained to a tree. Horrified, he broke her chains, and ran to Lhavit, stopping for nothing, riding his horse almost to death, and when it had to rest, travelling on foot the rest of the way. When they reached the city, he took her to a healer, and after she recovered, took her to his home. There, he spent years taking care of her, until he was sure she could live on her own. Then, he left, due to family ties and duty calling him away. However, he promised he would be back, and Kesu is still waiting for him. In his absence, or in the absence of any person who might help her recover, her feelings have festered and turned to hate to 'Mother' and 'Father'. Everything she does now is to advance her ultimate goal of vengeance to those who tortured her, and to save others from the same fate.
The Arcane
During the years of recovery in Lhavit, Kesu, still scarred, but recovering, was fascinated by the magic all around her. Reading books, and learning from several quite informal teachers, she practiced, and although she is still a novice in the magical disciplines that she has learned, she showed a remarkable understanding of glyphs, and an almost instinctive auristics ability. To this day, she still studies the arcane arts, and plans to study more, eventually.