The reigning Queen and victor of the past two Queen's Blade tournaments. Primary antagonist.
As the title suggests, Aldra is the current queen, even though she uses several dirty tricks to win, such as turning her opponents to stone with a single glance from her right eye, which is not really hers but a thing granted by demonic possesion. Many times during the anime we are privy to the internal conversations that Aldra has between herself and the demon the she willingly allowed herself to be possesed with. The reasons for her doing this are really never very clear.
Some way or another, she is the antagonist behind every reason for every fighter in the tourney, from invading a neigboring country to depriving an orphanage of supplies. And she manipulates the fighters constantly, taking sadistic pleasure in their pain. Especially when she breaks Cattleyna's will be revealing that she had imprisoned the blacksmith's husband in stone.
Eventually of course Reina defeats Aldra in the final round of the tourny, with a lot of help from everyone else, and several rather random and ridiculous scenes that I will not repeat. What happens to Aldra afterwards is unclear.
Aldra was created for both the Queen's Blade and Queen's Blade Rebellion Visual Combat Books. Her appearance drastically changes from the original Queen's Blade to Rebellion. In both book Aldra was drawn by artist Kantaka. Her measurement from both series are: