Oroku Saki

The Shredder

 Oroku Saki was born in 1971 and raised alone by his father Oroku Nagi. While Saki was still a boy, his father was killed by Hamato Yoshi, leaving the young Saki full of hate. Saki is recruited into the foot at an early age, dedicating his life to destroying Hamato Yoshi and all that he represents. Saki's dark path of revenge leads him to mercilessly kill every member of the elite Foot and their families. As the legend of Saki grows, he becomes known to his enemies as Shuredda and earns the title of Japan's finest shinobi.

"Shuredda" means Shredder in english

Hamato Yoshi

 Inside the most elite ninja organization in the world, Hamato Yoshi is second in command of the Foot. Betrayed on his wedding day, Yoshi kills Oroku Nagi, violating the sacred code of the Foot. Yoshi's punishment is lifetime banishment from his home and country. Starting over in New York with his wife Tang Shen, Yoshi finds peace opening a martial arts dojo where he mentors troubled teens. His peace was not meant to last.

Splinter

 With the sudden loss of his beloved master, Splinter found himself wandering the sewers without purpose. Crawling into a strange green substance, Splinter's body and mind transform allowing him to realize everything he has learned as a pet of Hamato Yoshi. Unprepared for the role of a parent, Splinter chooses to father the turtles. Continuing the legacy of Hamato Yoshi, Splinter trains the turtles in the art of ninja giving them a place in society and a sense of purpose.

Baxter Stockman

 Graduating from MIT at the top of his class, Baxter Stockman's senior thesis titled 'Stopping cancer, fighting mutation with mutation' piqued the interest of TCRI, the leading scientific research organization in the world. TCRI creates a division for Baxter to research and develop his theories. Baxter and his team save millions of lives by using genetic mutation to stop cancer in its early stages. Successful at work, and happily married to his high school sweetheart, Baxter could not imagine a more fulfilling life. With Baxter's success, Oroku Saki becomes very interested in his research. Killing Baxter's team and threatening his family, Oroku Saki demands Baxter's indefinite cooperation. Baxter has no choice.