Aldra is the victor of the past two Queen's Blade tournaments and reigning Queen of the Continent. As the child of the Pope, the highest religious leader, and the daughter of the Devil King of the Netherworld, she is a cursed half-demon who, along with her sister, was persecuted everywhere they went. One day while searching for some food, Aldra's sister disappeared. She soon made contact with the fallen angel Delmore, whom she made a contract with and gained demonic powers at the cost of her growth. She then became determined to win the Queen's Blade and use her power to search for her lost sister. Because of her current position as Queen, she would often have fits of paranoia over the fact that someone might overthrow her, which led her to establishing the Assassins of the Fang. Her official English name is "The Queen Aldra".
Aldra has the ability to encase people in an amber-like prison through the use of her "Evil Eye", which is located on her right side hidden under an armored eyepatch. For close combat, she wields a broadsword called the Demon's Blade and has a hidden weapon called the Secret Cleaver located in the groin area of her armor, which pays allusion to BDSM. She also has the ability to summon shikigami called Minions to slow down her opponents.
In Queen's Blade Rebellion, after losing the title of Queen to Leina (later Claudette), Delmore, the source of her powers, was stripped from her body, and reverted to her true adult form after her defeat. She later embarked on a journey to find her lost sister, but suffered from amnesia along the way. During her journey, she fell in love with a man and was later married. Her happy life was short-lived when the war between the Queen's Army and the Rebel Army spread throughout the whole Continent. To protect her beloved husband, she was determined to throw herself in the fight, and made a contract with the Underworld dwellers Belphe and Dogor (an amalgamation of the demon Belphegor). However, both demons are secretly plotting to eat Aldra when given the opportunity. Her current outfit pays homage to the "naked apron" anime stereotype that is usually found in ecchi anime and manga.
Aldra was originally a villain in The Original Queen's Blade Series but in Queen's Blade Rebellion she became one of the Heroes who defeated The Swamp Witch.