Cause: The War of Karanii was caused by an infiltration of the planet Cosadine in 2192 AD by a band of rebel Ser'pin'tiik. Conditions of their villages were, needless to say, something worth fighting and dying for. They challenged the Serpen'taii, who at the time were ruling the planet, and there were thousands of casualties...43,210 fatalities, around even on both sides of the battles. Significant enough to the planet to shape how it is currently run.
Major Battles: Battle of Redigiir, Battle of Bloodmar Hill
Timeline: 2192 AD - Battle of Rydio Mountain, led by anarchist Court McClain, 2193 AD - Battle of Redigiir, 2196 AD - Battle of Bloodmar Hill, 2198 AD - Battle of Linomyre - Interference by a neighboring planet helped stop the war.
Heroes: Court McClain, Rachiim D'akur'aan, Adamine Shii'tappan
Lesson: Royalty must treat everyone equally, no exceptions. Fair rulers tend to last longer.