"Know ye, O Emperor, that in the years before the infamy of Tensho Iga No Ran (Iga ninja massacre of 1581), the crows whispered the secrets of the training of the Koga. Karasu said the Tengu would descend from the mountain top in a terrible wind, unexpected and unseen, to impart their occult abilities among the men, women, and children of the villages. The warrior disciples would gather in the shadows, and there they would learn from the Koga Tengu, the Ways of Invisibility, the ways of not being cut by sword nor stabbed by spear. The Ways of Not Dying. The Ways of Endurance.
"Know also, O Emperor, that this endurance training imposed by the Tengu was ever likened to enduring death, for they were demons; theirs was a hell dojo. So that no skill was left unlearned, no pain was left unknown. There was ice in their veins and blood on the walls. Wood, Earth, Fire, Water, and Wind attacked the disciples as enemies, until they let the elements become friends. And it was the ways of the Tengu that let the Koga persevere when the Iga lay crushed by Lord Oda. The Ways of Endurance.
"And it was their knowledge of hell, O Emperor, that let them escape it. From that day on, the Koga has kept the lessons of the demons hell. The Shadow Disciples are hanged on Wood. They are buried in Earth. They are drowned in Water. They are frozen and battered by Wind. They are scorched by Fire. There will be ice in their veins and blood on the walls. And they must always train in DOJO HELL."