The First Key was the key originally wielded by Mister Monday for 10,000 years, before it was claimed by Arthur in Mister Monday. It bestows control over the Lower House. It takes the form of a hand from a clockface. The First Key has the useful and unqiue capability of splitting into two, lesser keys - The Minute Hand and The Hour Hand. The two separate keys were soon fused into the Clock Sword.
The powers of the First Key are numerous, as such not all the powers are known. The known powers of the First Key are:
- Holding Back/Banishing Nothing
As of Lady Friday it is said the Keys can kill anything the wielder wishes, be it Nithling, Denizen, Superior Denizen or mortal. It is thought that beings not of those categories like the Architect, the Old One and their three sons (The Piper, Lord Sunday, and the Mariner) would not be affected by any such attempts. Also, later on in the series, it is thought that Lord Arthur would be immune as well. It is unknown if the Trustees are immune.