The Great Clans are the cornerstones of Rokugan. Originally, there were seven Clans, each formed of the followers of the Kami. The followers of Hantei became known as the Imperial Families and didn’t form a Great Clan. The followers of Akodo, greatest general and founder of bushido formed the Lion Clan, the paragons of honour and tradition. Doji, the fairest of the Kami founded the Crane Clan, who set out much of the rules of court and culture of Rokugan. For eleven centuries the Hantei Emperors almost exclusivly married a Doji bride, ensuring that the Crane Clan controlled the Imperial Court. This led to the Lion and Crane being traditional enemies. Bayushi, first Champion of the Scorpion Clan was entrusted by the Emperor to give the other Clans a villian to keep them from plotting against the Throne. The Scorpion Clan have fulfilled this role admirably, as no one trusts a Scorpion. Shinjo and her followers formed the Ki-Rin and left the Empire’s borders to seek out other threats such as the Shadowlands. Eight hundred years later they returned as the Unicorn Clan, masters of cavalry and bearers of gai-jin ways. The followers of Hida formed the Crab Clan and took on the duty of defending the Shadowlands border. Togashi, the most enigmatic of the Kami formed the Dragon Clan and retreated to the mountains to watch over the Empire and stand ready against the return of Fu Leng. The Phoenix Clan were a special case, as the Kami Shiba pledged to serve the mortal Isawa, one of the greatest magic users to ever have lived. Shiba knew that in the end, Rokugan would be a land of humans, ruled by humans and that the Kami should stand aside.
The eighth Great Clan is the Mantis Clan, founded not by a Kami but by a mortal man. In the early days of the Crab Clan, the son of Hida Osano-wo was passed over for his younger brother. He departed the land of his fathers and settled on the Isles of Spice and Silk. Others followed and they became known as the Mantis Clan, the first Minor Clan founded in Rokugan’s history. When the Clan War came, the Mantis Champion Yoritomo forged an alliance of Minor Clans and led them to fight against the true enemy, the Shadowlands. So it was that Yoritomo, on the dawning of the Second Day of Thunder demanded the other Great Clans recognise the Mantis as one of them. So it is that the Mantis Clan are the youngest of the Great Clans, born of ambition.