Rurushi Ru

Rurushi Ru (ルールーシー＝ルー) is a female vampire. She appears to be "Daywalker" type Vampire, which allows her to be active during the day like normal humans. Like all vampires, she drinks blood to revive her vitality and magic strength. When her energies are low, she can reduce her size/age to conserve energy. Her magic allows her to create shields/barriers and project illusion of magic clothes. She also notes she does not use her magical abilities in combat due to it tiring her out and reducing "firepower" in physical battle.

She has a keen mind, is knowledgeable about politics of her region of the world near and around the Forest of Death.

Known Early Life History
She once belonged to a kingdom and was friends with Angel Tia. However, "trouble" accrued in the Kingdom, in which these events forced her to flee the Kingdom.

Forest of Death & Fateful encounter with a Farmer
Having eluded her pursuers, she entered the Forest of Death, which eventually she would encounter a human alone farming. Inferno Hounds who happen to be living with him would rush to defend their master. However, the farmer holds them aside being happy see another "human". Desperate for energy, she bites on him and her vitality returns. However, seeing this as an attack. The inferno wolves attack her yet again until stopped by the Farmer, who tells him he is Hiraku Machio. He allows her to drain some blood to revive her strength. She interns from his kindness to allow her to stay at his humble home in the woods, develops a relationship with him and refers to him as "Honeybuns".

Trivia

 * Ru Rurushi has been noted as a "Vampire Princess" on manga chapter 127. This hasn't clarified if she really is royalty.
 * Though she never had a ceremony with Hikaru, they consider themselves married.
 * In the anime near the end of episode 10, it's indicated that she is pregnant with Hiraku's child.