Thank you for asking that question (Una’s identifying phrase). The evil heart is a product of pure and total ego, that is concerned only for oneself. It occurs fairly often naturally in the human world and occasionally becomes very powerful. It is these powerful people who are a great danger to the world. When their heart is destroyed, they turn into and reincarnate as various predatory animals. They are not so evil that they go to a hell realm, but if left in the human realm they cause much destruction.
Question is submitted by R.F.