Here’s an interesting post on Emotional Vampires. I’m not sure that I have encountered a person like this but I think the principles are important for any kind of toxic or abusive person. Here’s a quote:
“It is important to be decisive, direct and non-reactive when dealing with emotional vampires. Remember, emotional vampires can be quite charming. Establishing boundaries early will help. But, don’t be afraid to set a new precedent with an emotional vampire, even if you know they will react negatively. Set an intention that you will not be an emotional prisoner to anyone.”