Battle of Burning Shadows

The Battle of Burning Shadows was the breach of the Kaiu Wall by the returning Unicorn Clan. Fields of Victory, p. 40
== Preambles ==
In the year 815, a large force, most mounted on powerful warhorses, suddenly arrived in the southern reaches of the Empire having apparently traversed the Shadowlands. The travelers claimed to be the long-lost Ki-Rin Clan, now called the Unicorn Clan. For nearly eight hundred years, they said, they had wandered and explored the world outside the Empire, and now they were back. The Crab were unable to recognize them to let the Unicorn pass into the Empire. Fields of Victory, pp. 40-41
== Battle ==
In the ensuing battle, the Unicorn Clan Champion, Shinjo Nishijin led the returning clan. The Iuchi shugenja blasted a massive hole in the Kaiu Wall, and the hordes overran the unprepared Crab defenders. The Crab allowed the Unicorn to pass them by and regrouped to focus their efforts on repairing the Wall. The Unicorn took little time to rest before marching deeper into the Empire. Fields of Victory, p. 41
== Aftermath ==
In a series of successive battles, the Unicorn faced armies raised by the Lion, Phoenix, and Scorpion Clans. At the Battle of White Shore Plain, the Unicorn defeated a Scorpion army despite the underhanded tactics its commanders employed. At the Battle of Thunder Grove, the Unicorn thwarted a Lion ambush with a cavalry retreat that drew the Lion soldiers into a counter-ambush that destroyed them. And at the Battle of the Peaks, as the Unicorn hordes crossed the Spine of the World Mountains, a team of Phoenix Air Elemental Guards and the Hurricane Initiates attempted to ambush them, only to be rebuffed by spirits they did not recognize that answered the commands of the Unicorn shugenja. Eventually the Unicorn clan were recognized as the lost Ki-Rin Clan before they fought another battle with a well-organized Lion army prepared against cavalry tactics. 
Kaiu Wall