The Kalinga war turned Ashok life due to the following reasons:-
1.It was the only major war that Ashok had fought and in the war he had seen the bloodshed and extermination from his own eyes.
2. It is assumed that around 200000 lakh people were died during this war. For this Ashok held himself responsible for this.
3. Due to this, he ended the military expansion of the empire and embraced Buddhism and life of non-violence.