Discovering the RachniEdit
Salarian explorers opened a relay that lead to rachni and were captured by them. The rachni then created used the explorers star ships to travel through out the galaxy.
The Krogan's homeworld was devastated due to civil war. After the council was losing a war to the rachni for about a century the Krogan were relocated by the Salarians to a new planet. for the Salarians aid the Krogan aided the council in the Rachni Wars. The Krogan breeded very rapidly , were used to harsh enviornments and less effected by the Rachni's harsh enviornments.
The Krogan quickly overwelmed the Rachni and elimated their Queens. When the Rachni were pushed back to their homeworld Suen, they refusedto surrender. Then the Krogans detonated bombs on the rachni's homeworld obliterating the Rachni. Normally the Council would not approve of such drastic acts but, seeing as how violently unreasonable the Rachni were the Council had no objections. After such an incident the Rachni were considered extinct and the council made laws stopping explorers from going to uncharted systems to try to aviod otehr incidents like the Rachni wars.
enviornments than the other species ; the Krogan were also very skilled warriors.