Wordman/CalendarOfSetesh

The Calendar of Setesh is the canonical calendar of the Underworld, described in various parts of the Abyssals, particularly pg. 37. To my knowledge, no indication of how its dates actually function exists in canon, so it might as well work like this.

The Calendar of Setesh does not track time in the Underworld; it regulates it. Before the calendar's creation, time had no meaning to the Underworld and now Setesh can control the calendar to mean nearly anything he likes. He is, however, beholden to one constant that, though he would never admit it, is beyond his control: the regular occurrence of the Calibration in Creation. Calibration brings Creation close to the Underworld, affecting both realms, regardless of Setesh's desire. As a result, while he can speed, slow or even stop his calendar, Setesh usually chooses to run it in a rough analog to Creation's time, such that Calibration remains regular and predictable the Underworld's inhabitants.

Setesh constructed the calendar to measure four equal seasons, one for each aspect of the Dual Monarchy (Abyssals, pg. 54), with the additional observance of the five days of Calibration. The first season is named for himself, the male aspect of the Black Monarch. Next is Eset, the female aspect of the White Monarch. Nebthys, the female aspect of the Black Monarch follows, with Usine, the mail aspect of the White Monarch, marking the days immediately prior to creation.

Each season is divided into five months, each containing three seven day weeks. The months are named for the five ghostly elements: in order, ghost flame, jade, bone, blood and prayer, as can be seen in detailed view of the calendar.