From Guild Wars 2 Wiki
- Random drop from the weekly personal reward chest following completion of a Guild mission.
- After the devastation of the Guild Wars, the human kingdoms of Kryta and Ascalon banned guilds from owning land, and as such, guilds could only build their halls on one of the many islands that fell under the jurisdiction of Cantha. By decree of Emperor Kisu, the Celestial Ministry required proof that any guild who wanted a hall was favoured by the Five Gods, and the Celestial Sigil was deemed to meet that condition.
- It was said that the Celestial Sigil was granted to those brave and skilful enough to hold the Hall of Heroes and earn the blessings of the gods. To reach the Hall of Heroes, legends held that guilds must pass through the Underworld itself.