Jagaroth
The Jagaroths were a race of advanced, ancient humanoids.
Physical Characteristics
Jagaroths were lumpy humanoids with green, veined skin. They had a single eye on their forehead and two large flaps on each side of their face. They were also covered in small tendrils. They have deep, echoing voices. (DW: City of Death)
Technology
The Jagaroths had very advanced technology, such as human disguises and holographic technology. They also had access to advanced knowledge and impressive intellect. Scaroth was able to fool the humans and advance humanity to the proper technology level using just his wits and knowledge. Though they know the concepts of time travel, they didn't have the technology level. (DW: City of Death)
History
At some point in the distant past, the Jagaroth were involved in a war amongst themselves which nearly wiped out the species. Despite this, some of the Jagaroth were able to make it to Earth. They were planning to leave the planet, but there was a problem with the ship and it exploded. This explosion started the development of life on Earth and sent Scaroth into the Time Vortex. He was then split into twelve portions, which were trapped in different points in in the timeline. These parts of Scaroth attempted to change the development of humanity, so that time travel could be created and he could return to save his people. (DW: City of Death)