Black Butterfly is a powerful azata Empyreal lord. Per legend, the Black Butterfly was created by Desna accidentally; as Desna placed the stars in the sky she made a pattern that, upon completion, manifested itself as the Black Butterfly. She views the Dark Tapestry as the worst of all evils. The exact location of her residence is unknown, but is thought to hide in the dark spaces of the Stair of Stars, which leads to Cynosure, Desna’s palace.
Appearance

The Silence Between looks like the silhouette of a woman that also has white hair and eyes. Her wings contain images of planets, stars, and galaxies.
Church

The Black Butterfly is typically worshiped in monasteries, mountain peaks, and underground spaces. Her holy symbol is a black butterfly with a star on its thorax. Creatures she favors include celestial gloomwings, star monarchs, and yamahs. Her most obedient followers perform an anonymous charitable act each day. If the beneficiary is seen or spoken to, the follower must spend an hour blindfolded while praying, then tithe to a temple of the Black Butterfly or other good god.

The starknife of the void is a weapon designed by devotees of Black Butterfly and at one time could only be found among the faithful of her mystery cults. Over time, these weapons fell into the hands of those outside the cult, and now they crop up in odd places sealed vaults, underground treasure caches, the bottom of the sea—but always places where there is darkness and stillness. The starknife of the void is a +2 returning starknife. If the wielder scores a critical hit against a foe with a starknife of the void, it discharges a blindness/deafness spell affecting the creature struck. The target must succeed at a DC 14 Fortitude save or be struck blind or deaf (as chosen by the wielder of the starknife of the void). If the starknife of the void deals more than one critical hit to the same target, the target can potentially become both blind and deaf.