In the Shattered Mirror Universe, Teridax was a Great Being who attempted to stop Naju from reaching Atlantis.
When Naju hijacked the Enterprise in an attempt to reach Atlantis, Teridax was one of the Great Beings (the others being Orlin and Trahii) who tried to stop him. Teridax emerged from the Shattered Mirror and ordered Naju to return to whence he came. Naju responded to this by shooting Teridax and vanishing. It is unknown whether Teridax survived this attack because he has not been seen since.