"The Buddha told Kassapa: Seven hundred years after my Nirvana, the demon king Mara will gradually destroy my Dharma. Just as a hunter wears dharma robes, the demon king Mara will also do the same, taking the form of a bhikkhu, bhikkhuni, upasaka, and upasika. He will also transform himself into a Sotapanna, an arhat, or a Buddha. The demon king uses this defiled form as a pure body to destroy my Dharma." - The Mahaparinirvana Sutra