From the Glorantha Sourcebook (pages 41-42):
In Sacred Time, Kallyr Starbrow rallied her kingdom behind her to perform the Lightbringers’ Quest, a complicated heroquest that usually provided new life and health to everyone participating. Instead, Jar-eel the Razoress invaded the ceremony, killed most of Kallyr’s companions, and grievously wounded Kallyr before the Red Goddess was driven off. The failed ritual has brought terrible omens of crop failures, disease, Chaos horrors, and war.
Glyph is part of the great series of pictoglyphs on Black Dragon Mountain, often attributed to Cragspider’s magic, but actually by Simon Bray.