Cassisians may be the weakest angels, but their faith is strong and their perfect memory ability can make them precious eyewitnesses.
When donned, a helm in a treasure hoard unfurls its wings and reveals itself to be a cassisian. Its memory and protective aura are useful, but its constant sermonizing about the need to fight hobgoblins may alienate reluctant wearers…or drive eager disciples to rash acts of bravado.
A newly manifested cassisian’s form is that of a helmet of a recently fallen general. Assuming the angel and the general are one and the same, the cassisian’s spirit might know the battle plans that could save a nation—if it can be induced to remember its former life (if any).
The stereotype of the agnostic, deity-defying wizard is often overdone. Good-aligned wizards in Corym are quite mindful in their devotions, and summon cassisians to serve as their familiars, advisors, and confessors.
—Pathfinder Bestiary 2 26