The Rise of the Goa'leks. Ch. 3
A new race rose up unexpectedly due to two seperate groups of Cyberman and Replicators meeting each other and despite the hot heads desires for conflict. Cooler heads finally realized the advantage of a merging similar to the birth of the Goa'leks and after several trial and errors the Replicator Cybermen race was finally born. Immediately they had expanded themselves among the stars in galaxies beyond the Milky Way Galaxy and then when they found the courage they returned to the Milky Way.
Not that long afterwards they meet with and entered into conflict with the Goa'leks and the two major powers clashed over and over again repeatedly in a seemingly infinite number of wars against each other with Earth always stuck in the middle. Only having the Doctor, Stargate Command, UNIT, SHIELD, Avengers, and the Justice League as its form of defense in that ever going conflict.
Although the Earth Defense groups felt in relief that it hasn't occurred on Earth it self only on the Planets of her colonies and those of her friends/allies. That was still of major regret to them that despite all their victories to free those planets from enslavement and yet now they struggle even with their combined efforts to protect them from this horrible conflict between two new enemies who are actually hybrids of two different sets of actually two old enemies with simply new guises.
The Doctor finally went enough is enough I am going to play the only ace that I have left. I am going to go for help from my own people that I am going to reveal that with Clara Oswald's help that I have actually succeeded in actually succeeded in saving his own race the Time Lords and Gallifrey. Now he has decided that this is the only chance of success and salvation. With all their own Time Lord science, technology, math, culture, and knowledge/understandng from both peacetime and the Time Wars warfare are those with the best success in this conflict even with the abilities of both the Replicator Cybermen and the Goa'leks to steal the science, technology, math, culture, and knowledge/understandng of other races who would otherwise be more advanced and complicated. And that would be the risk for the Time Lords but it is part of their destiny and responsibilities as one of the greatest huminoid alien races especially since the Ascended Ancients have shown repeatedly and once for all that they won't take that destiny and responsibility in heart for themselves.