Luminous Valentine

Luminous Valentine (ルミナス・バレンタイン) is a Demon Lord, the fifth seat of the Octagram, and the True Ruler of Holy Empire Ruberios. She is the ruler of all the Vampires and one of the oldest demon lords.

Appearance
She is a cute silver-haired girl on the verge of becoming a woman. Her heterochromatic eyes glisten in deep crimson and light sky blue. This, among her many strikingly beautiful features, is the most prominent one. When her lips part, they reveal a set of pure white fangs. She is commonly seen wearing gothic dresses but seems to have a penchant for maid uniforms too.

Personality
Luminous is a usually haughty individual who basks in her superiority when sitting on her throne or when acting out her official position as a ruler. However, she has no problems with pretending to be a maid when it comes to hiding her true identity.

She also enjoys classy food and entertainment, so much that she asked for a musical exchange after watching the concert in Tempest's opening festival.

Background
She is the fifth to become a member of the Demon Lord Council. More than 2000 years ago, Luminous' Vampire country "Night Rose" was destroyed by Veldora. Thanks to Chloe's early warning, the residents were evacuated early. Over the next few centuries, she established Ruberios and became its ruler in the shadows, having Louis Valentin pose as the ruler on her behalf.

In the years during aforementioned events, she became best friends with Chloe and Hinata. As they disappeared from Hero Chloe's body (due to Chloe and Hinata's younger selves entering the Central World), Luminous sealed the body away to prevent Chronoa from rampaging.

Trivia

 * She addresses herself as "warawa," which is an archaic pronoun used by women in samurai families. The author admitted that he intended to paint her as a haughty noble this way, not knowing that it's actually a self-deprecating, humble pronoun back then.
 * She has obvious yuri tendencies towards Hinata, shown by her enjoyment in making Hinata wear revealing clothing as well as seeing her naked in the bath. Same goes to Chloe, except that she doesn't have much chance to act it out.
 * Luminous has shown no such interest in men, meaning her orientation is lesbian.