Do vampires exist? Yes, but not the way that you and/or the average person thinks. It is true that entities exist that can drain not only energy, but also blood from you or related. I covered that in below video, that you’re welcome to watch of course.
But there are other common forms of vampirism that hit closer to home, so to speak; someone abusing or taking advantage of someone else in the most negative or diabolical of ways can also be classified as vampirism. Being a freeloader or a leeching parasite also counts as such, since you’re profiting off of someone else’s work rather than pave your own way. And it just goes on..(even mosquitoes and (certain) bats are vampires in a way lol).
But within a magickal or spiritual context, is it possible to drain someone’s energy? Yes. I can easily do so by targeting someone or something, and doing so. The person will feel lifeless and incredibly weak. Their astral body (spirit) will have to replenish itself, which will take time (depending on the person’s personality, strength etc.). Of course despite the fact I can do so, I have to take things like Karma into account & whatnot; I can’t, nor would I do something like that willy-nilly, even if warranted and/or justified. I for example took away someone’s magickal power when it was fully validated, which is very similar in nature (but permanent in this case). The entity Baku, the sin-eaters from old are more examples of vampirism, the way succubi can be seen as sexual vampires. These creatures as well: