In the 300’s, a Tengu demon known as the Shredder ravaged Japan and had plans to conquer the world. The Japanese Emperor summoned the greatest warriors of the country, Kon, Juto, Chikara, Hisomi, and Oroku Saki, the most skilled of them all. Each was armed with mystical armor and battled the Shredder, emerging victorious after Saki managed to bring him down. However the tengu contacted him on the astral plane before he could land the finishing blow and made him an offer, in exchange for his soul, he could have great power and conquest. Saki’s darker half made him accept, invisibly the tengu’s soul and his own merged and his lifeless husk turned to dust. The five went back to the Emperor, who named them the Five Dragons and gave them the symbol of “Three-Toed Sign of the Dragon”. However Saki revealed his malevolent powers and took on the identity of the Shredder, taking over Japan and adopting the symbol himself turning it upside down giving it the appearence of a foot.
The other Dragons went around the world to learn new skills from mystical masters to find a way to defeat saki and eventually returned, having become far more than mortals. In a mystical battle, the four fought the Tengu Shredder and manifested their worldly avatars to defeat him. However he could not be destroyed and was sealed into a coffin by the Dragons, who hid away his helmet and gauntlet, which would bring the dark one back if they were ever reunited. To get help to make sure he never returned, the Dragons formed the Ninja Tribunal, which taught their secret arts to worthy and good warriors.
A few centuries later, Ch'rell an evil alien Utrom took up the name of the Shredder, using the Tengu Shredder's name to gain fear and respect. However the Ninja Tribunal never saw Ch'rell as the true Shredder believing him to be just an alien bug.
Before the Tengu Shredder was sealed he created five heralds known as the five Foot Mystics to set him free were bound by a amulet known as the Hear of Tengu which limited their power and gave whoever owned the amulet to keep control of the Mystics. The amulet later got into the hands of Ch'rell.
Ever since the defeat of the Tengu Shredder, the Mystics had made some attempts to bring him back, the Mystics had sent a Bone demon in the early 21st century, hidden by the power of an amulet, to find the Lap of the Gods, so as to bring back the Shredder. However the young Ninja Turtles along with their Master Splinter and the ancient one were able to bring an end to the demon by destroying the amulet.
The Mystics later tricked Agent Bishop leader of the Earth Protection Force (EPF for short) into destroying the Heart of Tengu which was stolen by Karai from the Turtles, as the Metal Mystic made Bishop believe there was secret alien data implanted in the amulet. The Mystics were then free of Karai and went off to bring back their Master, by this point the Mystics hated Karai for taking the image of the Shredder like Ch'rell her adopted Father did before her.
They managed to get the gauntlet and helmet, defeating the Ninja Tribunal, and brought them to New York, where they finally revived Tengu Shredder. He decided to get his revenge on Karai for taking his identity and hunted her down in the Oroku Saki Memorial Library. She was able to fight him off with magic-based weaponry Dr. Chaplin a Foot scientist had made, but his helmet was knocked off and his face resembled that of Ch’rell’s android suit. This distracted Karai enough for Tengu Shredder to catch her off guard and transformed the sword she’d stabbed him with into a snake monster, which he sent to destroy her. Eventually the snake had Karai wrapped up against a pillar and it and Tengu Shredder both attacked her, but he accidentally beheaded the snake. Angered, the demon warrior used his magic to pin Karai against a wall and stripped her of the Shredder armor. The Tengu Shredder considered letting her live as a slave, but the Ninja Turtles interfered, allowing Karai to break free. He summoned his army of demons and the undead he had amassed over the years, transforming the tower they were in into a graveyard. While his minions held Karai in place, Tengu Shredder prepared to finish her off, but Chaplin tried to protect her. Seeing he was in love, the demon warlord decided it time was to end this and managed to wound Karai. But the Turtles summoned their Dragon Avatars to fight the Tengu Shredder, making him and the Foot Mystics retreat and, looking upon the new modern world, he planned to reshape it and make it his own. The Tengu Shredder took control of the Mayor’s office, transforming it into his citadel and begun spreading his magic arcross New York making it a world of monsters. Since he needed more energy to complete the transformation, the Foot Mystics had made the city officials created keystones in a triangular shape for amplification. The Turtles tried to stop the spell, but the Tengu Shredder found out, getting angry that he wasn’t told by the Foot Mystics. He stopped their plan so the transformation was successfully strengthened. The Turtles gathered together their allies and enemies such as Bishop and Hun a former guard of Ch'rell the Utrom Shredder and now leader of the criminal organization the Purple Dragons, to lunch a final attack on the Tengu Shredder and Karai had a means of draining his energy so they could take his gauntlet and helmet to weaken him. This worked and Tengu Shredder was rendered unconscious, but Hun kicked him to ensure he was done, waking him up.He blasted Hun away then transported Splinter, the Ancient One, and the Ninja Turtles outside and mounted a demonic horse to take them down. After bringing down the Turtles, the Tengu Shredder attacked Splinter when Hamato Yoshi appeared from the Turtles’ medallions. Taking the Shredder’s trident from him, he drove it into the demon warlord’s armor, making him lose energy. To restore himself, Tengu Shredder turned New York back to normal and transformed into a dragon, with the Turtles doing the same like the tribunal did long ago. They continued to battle and the Tengu Shredder proved too strong, however Karai began draining his energy again. He went to destroy her, but the Turtles got in his way and started fighting back. Eventually the Tengu Shredder got so weak, he returned to human form and desperately launched one last charge, but was knocked around so that he dropped his helmet and gauntlet.
The Turtle Michelangelo snapped the helmet in half and Leonardo stomped on his gauntlet, rendering both useless. As the Turtles regained their humanoid forms, the Tengu Shredder was slashed in half by the ghost od the Utrom Guardian Yoshi the Master of Splinter, ending him once and for all.