War of Green Rock

The Dheizei and the Basadu do a very good job of coexisting, for the most part. Probably courtesy of their shared oppression at the hands of the Garruw, and their unification being one of the things that helped bring that to an end. But they are very different people, in the end, and they share a large swath of the same space.
In around 450 PD/E, something happened and the Dheizei attacked the Basadu. (This was likely caused by the Basadu doing something in the first place) (also note that this starts before Katolu Federation was a thing).
This led to a formal declaration of war between the collective Dheizei tribes and several of the Basadu cities at that time. Important to note that the Dheizei acted as a collective (for the most part, and not to say that they all agreed, but any disagreement was internal) while the individual Basadu groups remained so. This did not change how they were attacked, though, as no specific reason was given for the initial assault by the Dheizei.
It took five years for the conflict to be resolved, and then it was only the actions of the leaders of both sides that decisively ended the war. Secret negotiations were revealed during what became the final battle, as the leadership of both sides pushed their way to the front and stood in the path of the fighters.
It is important to note that the primary forces driving the battles were political, and those who stood in the way were the ones directly involved in the military.
While it's not the only strife between these two ethnicities, it was the most prolonged and focused.

Conflict Type

War