
Mister Monday is the possessor of The First Key. In the case of Mister Monday, he has the sin of 'Sloth' - extreme laziness. Unfortunately, though originally pure of heart, absolute power corrupted them, in different ways, absolutely. 'Mister Monday' can go to Earth on a Monday).

They were also forbidden to enter the Universes outside of the House (the 'Original Law') but they and their minions are capable of going to any place in existence on the day with their namesake (i.e. They were each given one of seven Keys, and the House split into seven Domains, each Day ruling one of these Domains - having absolute power in their Demise. Arthur Penhaligon is not supposed to be a hero. They were seven of the Architect's favourite Denizens and were placed in charge of the The House (in absentia). Mister Monday by Garth Nix: 9780807216583 : Books On the first day, there was mystery.

The main antagonist in this story is Mister Monday, one of the seven Days against whom Arthur must face off. Arthur is considered by most to be a reimagining of Arthur Pendragon, or the legendary King Arthur, who (it is prophesised) shall return again (like Jesus) to rid the world of evil and make Earth back into the paradise it once was. It also introduces Arthur Penhaligon, the Rightful Heir to the House and main character of the series. Mister Monday is the first installment in the 'Keys to the Kingdom' series of novels, written by Garth Nix, which take place in a strange realm known as the House.
