He had his own mother killed
Agrippina the Younger, Nero's mother, made her own preparations for her son to succeed her as emperor. She first murdered her first husband in order to marry Emperor Claudius, and she later murdered Claudius in 54 AD, as well as his son and legitimate heir Brittanicus in 55 AD.
The Praetorian Guard, with whom she had a partner to easily accomplish this, then promptly proclaimed Nero emperor. It would be an understatement to say that Nero's mother was a terrible person! One of Nero's most intriguing facts is that his rule was not characterized by the unpredictable behavior that would come to characterize it.
He really acted quite the contrary up to the year 59 A.D., reducing taxes, forbidding bloodshed in arenas, and abolishing the death penalty, among other acts of compassion and clemency. This didn't continue though, as historian Tacitus asserts that his mother's interference in his private affairs, especially his liaison with Poppaea Sabina, caused him to assassinate his mother in the year 59 A.D.
