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
Luminous was created by the Ancestor Twilight Valentine whom they considered their masterpiece. Eventually she became tired of her creator's antics and ended their life with a Disintegration spell. She took control of the remaining vampire forces and subjugated the powerful and bloodthirsty Vampire known as "Valentin". However Valentin became a problem as he would antagonize her other subordinates eventually forcing Luminous to split them into two separated being Louis and Roy. Sometime after she acquired Gunther who swore allegiance to her and served as a noble who assisted her rule greatly and in addition to serving as her personal butler.

She became the fifth member to join the Demon Lord Council and 2000 years later, her 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 act as the ruler on her behalf. Luminous herself would also have Roy Valentin “replace” her on the Demon Lord Council, with her secretly attending Walpurgis Banquets by pretending to be one of Roy’s two aides.

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.