Maybe Djer was one really mean dude! Who just lived and lived and killed all who oposed him! Such things have happened—think Franco in Spain.
I don’t know if Djer was a mean dude in life, but he certainly was after he died. During the first dynasty, it was customary to kill the king’s servants, concubines, jesters, and even dogs and donkeys, and bury them in graves surrounding the tomb, so they could serve Pharaoh in the afterlife. Djer got the most “satellite burials” of anyone = 318! In fact, a recent National Geographic article suggested that the first dynasty was overthrown in a revolution, led by those servants who didn’t want to die when their master did. None of the pharaohs later on practiced this custom; instead the priests buried them with statues and pictures of servants, who were supposed to magically turn into the real thing.