The Dog Star Gang are a Japanese criminal syndicate led by Chien Khan and his inner circle the White Ninjas and Ninjara, they were formed by Chien to aid him in fulfilling his deal with Noi'Tai'Dar, and for Chien to personally get revenge on his old gang who betrayed him, The Golden Triangles, especially their leader, Johnny Yen. The DSG were first met by the TMNT in Japan, where they prevented the sacrifice of a girl whose death was meant to bring Noi'Tai'Dar to Earth.

The 2nd time the DSG surfaced was in a turf-war in New York with their rivals and Chien's former gang, the Chinese street gang Golden Triangles, April O'Neil found herself in the center of this gang war, and though she initially seemed to have an alliance with the Golden Triangles, upon realizing how evil their leader Johnny Yen was, she and Chien maintained a very brief uneasy alliance to defeat him.