The Tengu named The Shredder was the earliest known incarnation of a being by that name. The exact origins of the Shredder Tengu were unknown; in the year 300 AD, he suddenly appeared in Japan and went on a rampage. The Tengu Shredder's goal was to subjugate the world and to turn it into his own personal empire full of agony and destruction.
To combat the seemingly-invincible Shredder Tengu, the Emperor called upon the Five Dragons: Kon, Juto, Chikara, Hisomi and Oroku Saki. Equipped with magical armor by the Imperial Court, they set out to fight the Tengu Shredder and managed to overpower him. However, just before Saki delivered the final blow, the Shredder Tengu contacted him telepathically, and asked Saki to take his soul in exchange for almost unlimited power. The ambitious Saki agreed to the offer and let the demon's soul merge with his own before he destroyed the Tengu's body with his sword.
The soulless husk dissolved into smoke, but the demon lived on through Saki; in time, he became known as the Tengu/Demon Shredder, the first Human incarnation of the monster.