Mordecai’s edict gave free range for Jews to use lethal force without penalty against any who attacked them. So in most places, people decided that maybe it wasn’t worth attacking them. Some people in started pretending to be Jewish in order to protect themselves from possible violence.
Nevertheless, the fatal day came, and there was pitched war in Susa, and presumably in many corners of the empire. In Susa alone hundreds were killed, but the Jews graciously refrained from plundering those they defeated.
When Ahasuerus got report of the causalities, he accosted Esther in amazement and wondered what violence and bloodshed was occurring elsewhere? Esther begged her husband to allow the mob violence to continue for just one more day, and to execute Haman’s ten sons, who had been taken prisoner in battle. Sighing, Ahasuerus agreed.
In the end, the body count in was in the thousands. But, as seen is previous books, the Jews retained their high station and royal favor. They also declared a feast day and that’s where the holiday of Purim originates.