Kaya is Erika and Iori's mother. Estimated to be 251 years old and above, yet she looks like a child, giving people the image that she is Iori and Erika's younger sister instead. Erika looks like a splitting image of her, the only difference being Erika's more matured body and that Kaya's eyes are constantly red in color, which every vampire has when they have their vampiric impulses.

(source: Wikipedia)