Zodat

The Zodat were a race from another dimension accessed by the transdimensional network.

Biology
They were humanoid, grey skin and green pupil.

History
According to the archives the Zodat began with a great period of unrest but the Great Lawmaker Motis Priam, passed the Thirty-Two Precepts of Compassion ending the conflict.

The Zodat were one of the many victims of the interdimensional traveling Brotherhood who tricked them with peaceful occupation, allowing their armies to conquer and devour the Zodat. To prevent other worlds from falling to the same fate the Zodat destroyed their transdimensional gate, and left a message to warn any others of their fate. The entire Zodat race was rendered extinct after the Brotherhood devoured them as a food supply.

Culture
By all accounts the Zodat were a peaceful technological advanced civilization.

Source

 * TMNT: S04E18 Trouble with Augie