It all started with two twin brothers, and their sister. They were born to a wealthy royal family that has bred world leaders for a long time. Their sister was the oldest so she got the primary title of Kingdom. One twin got Company and all its colonies, the other one got Empire and all its vast territories.
Between Empire & Company lies Kingdom, which was the cause of all of their conflicts. In fact whatever the sister has, is the cause of all their conflicts.
Roughly every ten years or so, the brothers have some quarrel. It all started when they were ten and fought for the sand castle their sister built. When they were twenty and just got their holdings, they felt that Kingdom, yet to be inherited, is fair game and fought a bunch of skirmishes on its borders and in colonies. Then, when they were thirty, Empire invaded Company through Kingdom. At the age of forty, they riddled Kingdom with trenches and set the world on fire.