Hybris was personified spirit (or goddess) of hubris, arrogance, and insolence. Her Roman equivalent was Petulantia. Hybris was either the child of Erebos and Nyx as claimed by Hyginus, or Dyssebeia, the spirit of impiety, in Aeschylus Eumenides.
She is rarely referred to in myths but appears indirectly throughout character's actions, taking root in many Greek heroes that later becomes their undoing. Hybris was often regarded in myths as man's downfall and the ruin of cities, often scorned upon.
In Aesop's Fables, during a period where all the gods were getting married, Polemos (War), the last of the bachelors, wedded Hybris, as she was the only one without a husband. Koros (Insolence) was presumed to be the child of their union. It was said that Polemos soon grew fond of Hybris, following her everywhere she goes. This is why people shouldn't allow Hybris to breach their nation's borders because war (Polemos) will follow.