Narcissists HATE people talking. Why? Because they can't control what is said. They don't know what is said. That creates uncertainty and reduces their power.

And yes, they will happily talk behind others' backs. Create falsehoods, narratives. But when people speak, they will realise conflicting narratives and might get suspicious.

Look for a few things:

1. who wants to be the central node of communication in a group

2. who gets upset when people speak

3. who speaks behind other's backs

If someone gossips, they'll gossip about you too.

If they betray your secrets once, they'll do it again.

As long as people don't talk to each other, they probably will be unaware of this.