The enigmatic founder and head of the Enfant organization. Very little is known about his past before 1999, when he used his Gift to open the Door of Truth in a failed attempt to plunge the world into a total war, which, as he believes, is its natural state. His attempt was foiled by Colonel Richard Burton, so the conflict only broke out locally, in the country where the ritual was held and where the Enfant HQ was later situated - in Gazth-Sonika. To repeat the ritual and complete what he has started, Monday has been ever since searching for the two missing Holy Books (he managed to keep Firstari) and another person with a strong Gift, as he is no longer able to use his own, allegedly, because the right half of his face (which he always hides it behind a mask) is disfigured by Burton's bullet. Although it is not stated explicitly within the series, according to Kōichi Mashimo's vision, Monday was once a talented artist.