Mjölnir

Mjölnir (pron.: MYOL-n(ee)r; also Mjǫlnir, Mjollnir, jölner or Mjølner) is the hammer of Thor, the Norse god of thunder.

Lara Croft sought the hammer in Tomb Raider: Underworld.

History
Thor wielded Mjölnir in many battles harnessing it's massive power, making him a deadly warrior. Despite this, Thor eventually fell in Battle.

Odin separated the hammer from Thor's gauntlets and belt which allowed him to wield it, placing them within treacherous temples that would stop anyone who was unworthy of wielding Mjölnir from obtaining it.

Centuries later, Natla, who sought to begin the seventh age, employed Richard Croft to find the Mjolnir. Croft found one of Thor's Gauntlets' in a temple in Thailand, however, having discovered Natla's intentions, Croft, destroyed the map which revealed the locations of the other pieces, and hid the gauntlet in the catacombs of Croft Manor in a hidden office, along with a copy of the map for his daughter Lara.

Natla later tried to force Croft to reveal the locations of the other pieces, however he refused leading her to kill him.

Some time later, after another failed attempt to start the Seventh Age. Natla was discovered and captured by Amanda Evert. Amanda was seeking a way to reach Avalon (which was also the Norse underworld Helheim) which Natla saw as her opportunity to once again try and locate Mjölnir and gain access to Helheim, and helped her.

Amanda knowing that Lara Croft was also seeking a way to Avalon, followed her to the Mediterranean Sea, where she discovered Thor's gauntlet. Amanda's mercenaries stole the gauntlet from Lara, however, Lara had already put the Gauntlet on, which meant that it would be bonded to her until her death.

Lara made her way onto the ship where Amanda was keeping the gauntlet, and met with Natla who told her of the link to Helheim and her mother's disappearance, in order to give Lara the drive to find the other pieces. The ship began to sink, due to damage caused by an explosion that resulted from a botched attempting to kill Lara. As the ship went down, Lara saw Amanda, who returned the gauntlet, allowing Lara to do the hard work in retrieving Mjölnir.

Lara sought out the other parts of Thor's armour, tracking his other gauntlet to Thailand. However, Lara discovered that the gauntlet was gone, and that the map showing the locations of Thor's Belt and Mjölnir had been destroyed, with a message from her father to Natla, telling her that she would never get the power of Mjölnir. Lara suddenly realized that her father had signed using his full name, which he never did so as to distinguish himself from his own father for whom he was named after. She realizes that she knows exactly where her father hid the gauntlet.

Upon returning to Croft Manor, Lara descends into the Croft family Crypt hidden beneath the manor, discovering a secret door hidden beneath her grandfather's grave. This eventually leads her into her father´s secret study where she kept a copy of the map and the second gauntlet.

The look for Thor´s belt took her to Southern Mexico and finally to Jan Mayen Island where she recovered Mjolnir.

With the hammer Lara easily defeated Amanda´s mercenaries on her ship near the Andaman Sea. There she found Natla and interrogated her for her mother´s location. In order to enter Helheim both a ritual and the hammer where needed so Lara and Natla struck a temporary alligeance to get there.

Once inside Helheim Natla betrayed Lara and activated the Midgard serpent, a powerful device that would bring the end of the world. Lara was able to stop the mechanism with the help of Mjolnir only to throw it into Natla afterwards, plunging them both into a pit of eitr.

Powers
Mjölnir is one of the most powerful and deadly weapons on the world.
 * Weight and Density: Despite it's small size, Mjölnir is incredibly dense and heavy, one swing is capable of shattering glass that was strong enough to even keep Natla contained, and shatter massive stone structures. The hammer is so heavy, it can only be lifted by someone who has acquired the gauntlets and belt.
 * Electricity Manipulation: Mjölnir could summon lightning on command, powerful enough to send an average man flying, or fell the largest of tralls with ease the small Thralls will fall with one strike but the Yeti Thralls will require two or more strikes. This electric power was powerful enough to hurt Natla and that is something she could withstand shots from pistols and guns. When Lara found Mjölnir around it was a strong lightning storm.
 * Key to the Underworld: Mjölnir could be used to gain entry into any of the Underworld, being shown to open Helheim.
 * Slaying Monsters: Mjölnir is one of the most deadly weapons ever constructed, being capable of killing giants and even the Midgard Serpent. Even Natla was afraid of what this weapon could do, as she cowered when when Lara was about to swing for her, baring in mind, Natla's could shrug off gun shots as though they were nothing.

Design
Distinctively shaped, Mjölnir is depicted in Norse mythology as one of the most fearsome weapons, capable of leveling mountains.

Mythology
Though generally recognized and depicted as a hammer, some claim Mjölnir is actually an axe or club but misconceived as a hammer. In the 13th century Prose Edda, Snorri Sturluson relates that the Svartálfar Sindri, the brother of Brokkr, made Mjölnir while in a contest with Loki to see who could make the most wonderful and useful items for the Gods and Goddesses in Asgard.