Shinjo's Law

Shinjo's Law forbade an Unicorn to kill another.

Ki-Rin's Exodus
During the Ki-Rin's Exodus desperation made for short tempers. Otaku Shiko and Iuchi drew weapons against each other over the need to kill horses to eat. The Kami Shinjo stopped them and edicted the law.

Duels
All duels between Unicorn were fought with boken or shinai, so no blood could be spilled.

Broken
This law was broken for first time when a young samurai-ko pulled her wakizashi, and the shugenja she faced, fearing his life, killed her with a spell. The shugenja committed seppuku to atone for his defiance of Shinjo.