Tsar Lunar XI's Sword

Tasr Lunar Xl's Sword is the only relice that in the Guardians's possession.

Origin
The first artifact obtained by Guardians was the only remaining piece of the spaceship, the moon cilpper that the Man in the Moon was able reclaim, the sword that belong to his father, Tsar Lunar XI, The last ruler of the Golden Age MIM presented the sword to the Guardians as a tool to help them in their battle against Pitch, and Ombric decided the sword was meant for North, who wowed to wield it wisely and well. However the sword became petrified as a result it was rendered useless.

Looks and Functions
The sword itself of unusual design and capable of changing both its from and material.