Narcs with their own kids- could u see any traits?

If you had a XN with kids(that were not yours) could you see any inherited N patterns in the kids?

My XN had 2kids under 10. One was very very attention seeking and also could pick up when I was feeling vulnerable or uncomfortable in a situation so would make some cruel remark(often in front of other ppl) to make me feel worse. Other one would tell my eldest child all the time that he(my son) was stupid and no good at anything, even though he had been told no to as my boy has severe confidence problems. XN's child(same one) would also come round my house and smash up things in my garden with a hammer(eg two of my kids' sit-on cars, garden lights) then say nobody told him not to do that. He would NEVER smash up anything at his own house or anywhere else, just my house.

I can def see a pattern repeat esp since XN is the only parent in the picture so their only influence.