Yes, that's a girl.
Yes, that's a girl.

Name: Mjölnir
Origin: Toaru Majutsu no Index
Gender: Female
Classification: Former human, Magician
Age: Unknown
Powers and Abilities: Super strength, speed and durability, magic, lightning manipulation, shapeshifting, regeneration (high-mid), immortality (type 3) can survive in space, flight
Weaknesses: Abilities which can prevent Mjölnir from flying would more or less immobilize her
Destructive Capacity: City level+ (capable of vaporizing a third of Radiosonde Castle, a floating landmass the size of a city, could threaten Kanzaki with her attacks)
Range: Hundreds of meters, several kilometers using the form of the hammer
Speed: Hypersonic+ (able to keep up with Kanzaki), massively hypersonic reactions
Durability: City level+ (could take Kanzaki's kicks), regeneration makes her difficult to kill
Lifting Strength: Average human
Striking Strength: Class PJ
Stamina: Unknown
Intelligence: Average
Notable Attacks/Techniques:

- Transformation: Mjölnir has shown the ability to change its body into a variety of different forms and shapes. Not only that, it has also been shown to split its own body into hundreds of different pieces. Some of the different transformations shown were a sphere, a cylinder, a ball, a cross, a giant hammer, hundreds of butterflies, and hundreds of cubes. It has also show the ability to turn parts of its body into several matchlock guns and crossbows, with ammunition that can fire at subsonic speeds.

- Electricity Manipulation: Mjölnir is able to release bursts of lightning which spread out in all directions within a radius of 400 meters. The attacks are powerful enough to damage Saints such as Kanzaki.

- Throwing Hammer: By transforming into the form which corresponds with the hammer of Thor, Mjölnir can create a powerful blast capable of vaporizing a third of Radiosonde Castle after rotating its body at hypersonic speeds in a giant circle with a 20 kilometer radius for several seconds. The blast of lightning is fired directly through the center of the circle, destroying everything within 6.6 kilometers.

Notable OBD Victories:

Notable OBD Losses:

Other: Not to be confused with the hammer of the same name from Marvel Comics, or with the one from Norse myth.
http://img31.imageshack.us/img31/3275/300pxmjc3b6lnir.jpg