I dreamed that my dead relatives were killed.

Dreaming of someone's death in a dream often means separation. Of course, the person who died in the dream doesn't necessarily mean him. Maybe you have someone you like leaving you, or you are afraid that he will leave you, so you will have such a dream. It is superstitious and unscientific to mechanically say that dreams represent good or bad luck.

Former Duke of Zhou:

Anyone who dreams will die. I dreamed that touching the dead body was for profit, that the dead body was in chaos everywhere, that the emperor collapsed in Jichang, that my parents and brothers were the dead, and that my relatives and friends were the dead. I only dream of dead babies, arguing that the neighborhood is safe and the mother is safe.