Here's some clues about the Lightness War:
The main reason to Lightness War was to somehow test us, but we're not sure why this test was made and to what. The Lightness War begun quite lot of after Gorg War, about two years after it. Apparently Lightness, Gorgs and T-Race had made some sort of a deal between them. Gorgs left some information about the Lightness, but T-Race didn't give anything. At first Lightness targeted freighters and transports to somehow show us that they're now here. Also we first thought that Lightness had destroyed the remains of the Gorgs, but apparently this was false information.
Later a war was officially made with the Great Lightness, but T-Race wasn't helping. The so called T-Race resistance actually never existed, but the technology and help was given by the T-Race government. It seems that most of the Lightness' and T-Race's ships had no crew. It's unknown why they wasted so much ships in these so called "tests".
It appears that they had also made some kind of deal that only Great Lightness, Gorgs and T-Race come to this galaxy, not Healers or the other first ones. Also it seems that the Lightness, Gorgs and T-Race sent only quite light ships to here. It's unknown why they did the whole thing, but some people say that they're at war with someone.
More information comes, IF it ever comes available.