Sarnath

In the early issues of TMNT an alien entrusted the Ninja Turtles to protect an object of great power called “The Eye of Sarnath”. Much later o robotic being teared through the streets of New York with an alien creature named Quark at his side, this was revealed to be Sarnath, who was blind in a sense (he could see through Quarks eyes) and he was searching for his eye. 
 

Other Media

Sarnath never appeared in the TMNT’s first animated series, though he was mentioned in the shows first episode when the TMNT received the Eye of Sarnath from a dying alien, who in the comics was later revealed to be evil.