Anemon was a soldier of Krang's, pressed into his service as agreement for Krang to leave his people alone. However, when Krang demanded the coordinates of his home world to raid for food and Anemon gave him fake coordinates, Krang ordered his imprisonment. Anemon escaped, but was blinded in the process. He eventually acquired a symbiotic relationship with an eye-like alien known only as Eymo, who allowed him to see.
He was found by the Turtles several years later, who asked him to serve as one of the witnesses at Krang's trial. Anemon pretended to be enslaving Eymo and only caring for strength over weakness, so Leonardo proposed that if one of them were able to physically defeat him, he would have to come with them.
During his final fight against Leonardo, Eymo was separated from Anemon, causing him to panic. Eymo returned and allowed him to defeat a deadly cloud-beast.
It was then revealed that Anemon was crushed by the guilt of accidentally killing his people, and that only Eymo's influence gave him the will to live. With the assurance that Eymo would come with him, he agreed to leave the planet and testify at the trial.
Along with the other witnesses, Anemon was threatened by the assassin Hakk-R during the trial, but survived the encounter after Donatello intervened with a better offer.