Guys, I want to recommend you a book. I don't know if you know it. It's called "Toxic people" by Bernardo Stamateas. I was researching and I think there is an edition in English.
I really liked this book because it offers two perspectives: on one hand, what to do when we find a toxic person in your lives and on the other hand, what to do when we are being the toxic person.
The author preffers to talk about toxic emotions rather than toxic people bc who could be a toxic person for you, it's a right person for me.

It's not my intention to wake up distrust in you but to give you an insight about how avoiding some people who could take advantages of others who may seem weaker or have psychological issues.