Brusanta was fostered to the Tuatha de Bhriain by her mother Grainne. Not much is known about her father, Miach. He was at war and she was fostered in his absence. He, like Brusanta's mother and all their clann are believed dead. Their clann was probably overrun by the very clann that Miach had gone off to war against.

With all her people dead, Brusanta, chose to stay with the clann of her foster parents, the Tuatha de Bhriain. Brusanta's foster parents were one of the clann's warriors and his wife. She was taught to weave by the woman as most young girls and was taught how to handle a knife by her foster father. Being the wife of a battle scared warrior, Brusanta's foster mother also taught her the knowledge of herbs and their medicinal value. Brusanta's learning in this area was so keen, she was renamed after a useful herb....Valerian.