Splinter (or Hamato Yoshi) was a trained fighter in the arts of Ninjitsu and was to become a memeber of an elite group. Then Shredder or (Oraku Saki),a co-member took over the force and turned it evil, then making a sub-clan in New York - the footclan. Splinter could not be a part of this and so he left and was determined to stop Shredder. Then, by the secret ooze he and his rat came in contact with, he became a mutant rat and now is the sensei of the Ninja Turtles. He is a wise, knowledgable master who helps the turtles in other ways than physical. For if it weren't for him the turtles would not be ninja masters.