The Brush created everything.
Creation story told by Sylvester: http://mansionofe.comicgenesis.com/d/20160114.html
The Daynight was an important event in the rise of the religion. http://mansionofe.comicgenesis.com/d/20160222.html
Formal worship is in Temples headed by female Oracles.
Brushtival is celebrated in December and gifts are given. http://mansionofe.comicgenesis.com/d/20061207.html
The note for picture of the Founding Oracles calls the worship the "local area's current Human religion", but other species also mention The Brush.
Note on differences in the province of Erewhon: http://mansionofe.comicgenesis.com/d/20071227.html