I created this empire and gathered all these people. I defeated the Nanda dynasty and now its all mine!
Later...  
I am going to kill my brothers so I become the leader!
Kalinga
I want to kill everyone so I get more land!
 
It all started in 324 BCE when Chandragupta Mauryan defeated the Nanda dynasty and created the Maurya empire. 
A while later...
I feel bad for killing all those people. I am going to turn into buddhism and have peace.
Later, Chandragupta's grandson, Ashoka, killed all his brothers so that he could become the leader of the Maurya empire. 
Afterwards...
  
Later, there was a war in Kalinga, and Ashoka killed everyone so he could get more land for himself. The Maurya empire had a really powerful army since they used elephants. 
Lastly
natural causes
Later, Ashoka felt really bad for killing all the people. He turned into buddism and changed many conflicts into peace. 
Afterwards, Ashoka built hospitals, new roads to help with transportation, shaded areas for rest stops and more. 
  
In the end, Ashoka died because of natural causes. The kings after him were all very weak and this is the decline of the Mauryan empire.