Samurai Warrior Robot was a robotic fighter created by Krang in the image of a Samurai warrior. Its entire purpose was to battle the Hero Turtles.
Krang presents his initial diagram of the Samurai Warrior Robot to Shredder after complaining about Shredder's lack of success in eliminating the Turtles. He tells Shredder that the robot will be invincible, and once he has the first prototype, he'll multiply it by four.
After Michaelangelo and Raphael have a falling out, Mikey, Donatello and Leonardo leave the lair to go topside to catch a movie. They leave the sewers via the nearest manhole to their home and are immediately accosted by four very large Samurai Warrior Robots. The robots attack and the Turtles soon find themselves at a serious disadvantage. Fortunately, they are close enough to the lair for Raph to hear the commotion coming from above. He goes to check it out and sees the other Turtles engaged in a losing battle. Raph's first instinct is to throw a manhole cover at one of the robots and succeeds in separating its head from its body. Within minutes the other three robots have been destroyed.