Their levels of empathy, their relationship with their own ego, and, similarly, their levels of selfishness / egotistic/ egocentric. That’s the core that drives, they’ll make decisions on who to betray from that core, with no care for others, they become quite dangerous to be around. That said something people are good at pretending they have empathy and aren’t egocentric, but if you wait and watch, pretend always has cracks to see through. And i don’t mean small moments of overwhelm. I mean, polar opposite behaviours that seem outside their morals, when not in an extreme emotion. You will usually see little things around the edges, and your instinct is to excuse it away, because it doesn’t fit the narrative, don’t do that bit. Little things around the edges might look like casually stealing, possibly just small things, sometimes even from friends, jealousy or a hatred for someone for no apparent reason other than they’re good at something the person in question is, too. Wanting a lot of attention, without giving anyone else room in the spotlight, or giving less and less room for others in the spotlight, until it’s all about them. Passing blame, it’s always someone elses fault, or excuses for everything they do that they feel are a reason to be able to do the poor behaviour, rather than taking responsibility, learning and growing. Unable to metabolise failure, at all. If you look up fixed and growth mindset, (Carol Dweck) narcissistic types, always have a fixed mindset. Where they’re Unable to utilise mistakes or failures to learn and grow, and believe that you are inherently born good at things or not, rather than practice at anything making you able to be an expert at something.

I cannot remember the reference right now, but it’s said that anyone can become “genius” level at something, if they just put 7 years of practice into it. “Bad” people, practice being like everyone else, they are very good at learning what you want to see, and mirroring that, for a time, it’s not something anyone can hold up for very long, but that said, I’ve seen it held up for a year, odd, at times.

If you wait, don’t get enmeshed with someone too quickly, they usually try to move fast to enmesh you, and remember that a lot of what you see in anyone around you, is what your brain imagines is there, you put a “persona” on people, all people. What’s in everyone is a complex mix of a different set of morals, and emotional maturity, privilege and perspective of the world that’s shaped by their unique upbringing, surroundings and environment. Even two siblings can have very different upbringing, surroundings and environment. And everyone has bad and good, in them. What you need to assess is the harm they could or do cause you and what you need to do to keep safe, keeping in mind that psychological, emotional and verbal abuse, are as harmful as physical abuse. And then decide what level of involvement is safe for you.