Ashoke was an invadore, Cruel, & sarphira empire of Mourya.
That the concept was that "He is the most powerful man in
world who can able to expand more his emperial territory".
This was the cause of war
The Kalinga War was a war fought between the Mauryan Empire
under Ashoka the Great and the state of Kalinga, a feudal
republic located on the coast of the present-day Indian
state of Orissa. The Kalinga war is one of the major
battles in the History of India
the kalinga was unconquered state situated in between
tamralipti and dakshinavarta & it was causing problems for
trade between these two reasons of mauryan empire that's
why the war of kalinga was necessary