Mary Sue

Mary Sioux a.k.a Mary is one of the main antagonists of the series, the ultimate rival and the tool used by Being X inorder to stabilize a neutral war against Tanya Degurechaff. She is the sole daughter of Anson Sioux. Her real name is Mary Sue, which makes "Sioux" mistranslation.

Appearance
Mary is a young girl with brown hair and brown eyes. When she was still an ordinary citizen, she was seen wearing a blouse with long skirt. As a volunteered soldier, she is seen wearing an US military uniform.

Abilities
Prayer/Blessing Magic

The user can cast a spell by praying to Being X stronger than Tanya's powers. The speed is faster than an average human. Also, the firing abilities exceeds to Tanya's capabilities with 100% exact hit to the target.

She can blow a whole battalion (48 men) with only one artillery spell rather than Tanya's only can wipe out a whole company (12 men). However it reduce her mana to fifty percent of her full power e.g during her first mission as an volunteered soldier of US.

Rage Mode

The user's hatred and grudge to "Devil of the Rhine" becomes the source of the power. It exceeds to the limit of Blessed User. The operation orb of the user becomes brighter and regenerates mana quickly.

However the side of effects, the user lost control of its own movements and mindset.

Quotes
Catchphrase : "Curse you, Devil of the Rhine!"

(Mary to Tanya) : "I finally found you! Devil of the Rhine!"

Trivia

 * Her name "Mary" comes from the biblical character named "Mary of Nazareth".
 * She is the only person who can match Tanya von Degurechaff in many battles.