Observance Day was a holiday celebrated by the Keshiri of the planet Kesh's continent Alanciar. Held once every ten years, Observance Day featured plays, often celebrating the famous "Rock of Kesh", Adari Vaal. Its main function was to remind the Alanciari of the "Great Cause", their duty to resist any invasion by the Lost Tribe of Sith, a group of offworld Human Sith who resided on the neighboring continent of Keshtah Minor. Following the Sith conquest of Alanciar in 2975 BBY, Observance Day was phased out in favor of festivals which dramatized Jogan Halder's first contact with the Sith, who were portrayed as being benign and peaceful.
- Lost Tribe of the Sith: Pandemonium (First appearance)