Daphne is a Vampire who encountered Karin in her younger days. She and her twin sister Amethyst did not want to kill humans for food. Instead, they would seduce rich people, get taken home and then feed on them when they tried to make an advance on the sisters. Because they do not kill humans, they would have to run away after feeding.
For a while, they were fed by a village chief who took pity on them and would let them feed on him so long as they do not kill anyone. However, they were caught by his family who sent in the knights. They were captured and taken to Duke Eustace, the noble overlord of the region.
Daphne's sister Amythest was held as a hostage by Duke Eustace to force Daphne to do whatever he said.
Later, she and her sister are freed by Karin.