Nero receives almost no sympathy from Tacitus. At best, the emperor is described as eccentric, with a fondness for pageantry and self-indulgence. More often, Tacitus shows Nero to be a tyrannical and despotic narcissist with inclinations for cruelty, vengeance, pettiness, and indifference to the suffering he causes.
Tacitus describes how from the very beginning of Nero's reign, he was easily manipulated by his mother, Agrippina. Becoming fed up with this relationship, Nero had his mother killed so that he could rule without her influence. Tacitus describes this act as callous and cruel.
Tacitus also shows Nero to be a rather disinterested ruler. He is unconcerned with the suffering that his actions cause. He also rewards sycophants and punishes dissenters. He even decides to have his 14-year-old brother, Brittanicus, murdered for the trivial offense of being too serious at a drunken party (13.15).
It is important to remember that Tacitus grew up during the final destructive years of Nero's reign. He then served in the governments of Vespasian and Titus, who for political reasons wanted to paint the previous dynasty as corrupt and immoral. Therefore, while there is other historical evidence of Nero's crimes and cruelty, it should be remembered that there is an element of propaganda, gossip, and rumor involved in Tacitus' description.