Q: Where do evil spirits come from? The Christian Bible acknowledges them–Legion, for example (Mark 5:9; Luke 8:30).
It is important to understand that in all relative existence there are only the Supreme Spirit, God (Brahman), and the seemingly infinite number of individual spirits (jivas). The individual spirits live within God, which whom they are eternally one, yet distinct from him in a manner only the perfectly liberated spirits can comprehend.
There are not different kinds of spirits, but as spirits enter into relative existence and begin evolving through higher and higher forms, there is differentiation in the energies of which their various bodies are composed. For example, the body of a bird and the body of a human being are vastly different, but the spirit in those bodies are the same: pure consciousness. I recommend you read Robe of Light on our website for a detailed explanation of this and its purpose.
Types of unintentionally negative spirits
There are spirits that harm human beings but have no wish to harm. Some of these are spirits that wander into the world from other dimensions and wreak havoc, but with no negative intention. They just do not understand the world in which they find themselves and are not aware of the effect they are having on human beings.
Also very undeveloped spirits without understanding may harm human beings because they do not understand the nature of a human being. Undines, water spirits, often inspire swimmers to swim far out into the ocean in a kind of euphoric trance and then not be able to swim back, so they drown. The undines want the humans to join them and live in the water. But their influence causes them to die.