A pair of ninja members of the Foot Clan, Oroku Nagi and Hamato Yoshi, both competed for the love of a woman named Tang Shen. However, Shen only loved Yoshi, which enraged Nagi. Nagi attacked Shen, and in her defense, Yoshi attacked and killed Nagi. So even after Shredder was only fought with and killed off in one day, his shadow continued to haunt the Turtles for years to come, be it in the form of worm clones, the rest of his clan or Karai.