The Colorless December (무의 십이월, Mooeui Shibeewol; "The Twelfth Moon of Nothingness") is one of the 13 Month Series created by legendary craftsmaster Ashul Edwaru for the Princesses of Zahard. Together with its owner, Eurasia Enne Zahard, its sentient form was found in a psychotic state. Thus, both of them were sealed (봉인상태, bong'insangtae; "sealed state") away.
There is a rumour that this weapon drives the wielder insane should they not be the right owner. As a result of its sealing, Eurasia Enne Zahard is its current and only owner. 
Notes and Trivia
- It is unknown if the weapon drove the Princess insane or if it was the other way round. And if so, how or why. It is also unknown if an external factor was instead responsible for the state of the weapon and its wielder.