For the humans of Sanctuary, most of the time, they were on the side of the High Heavens.
The reason was simple. They were often persecuted and harassed by demons! Demons with a destructive nature were the natural enemies of all creatures. When humans faced powerful demons and were unable to resist, they would naturally side with angels.
However, over the years, many wise people appeared in Sanctuary. When they continuously studied and explored the relationship between angels and demons, they found that angels were actually not good people. The existence of the world of Sanctuary was a mistake. Be it demons or angels, they both wanted to destroy it. But compared to the tyrannical demons, the angels were just a little gentler.
Under these circumstances, humans were naturally more willing to accept the doctrines of angels and take holy light as their faith.