A Xindi-Reptilian
The Xindi Empire was a future Xindi governement which the Xindi-Reptilians could one day lead, according to the Sphere Builders. It would be truly united, and stronger than their 22nd century council-led alliance.
Given the way the Sphere Builders used this information to manipulate Dolim, it seems uncertain if they really foresaw such a future, or just made it up.