kabal of thirteen wizards perform a ritual
the raven queen was trying to prevent a war between gods, the wizards disrupted her plan. The Raven queen turned them into raven like bird creatures that could only obtain lore or magical power from the ruins of fallen civilizations

MAC remembers this relates to a journal in the language of Pandemonium with information on this group of wizards, ritual of the burning star. Their goal is to cause the return of the dark sun