Wha...? Our Soul Gems... turn us into Witches? If you were to use your magic so much that dirtiness built up and blackened your Soul Gem...If allowed to become completely dark...... Do you know what would happen?That is the inescapable fate of all magical girls.Will you simply become unable to use magic? No.......The moment a Soul Gem becomes completely darkened, your soul becomes overcome with despair, transforms into a Grief Seed, and you are reborn as a witch.