The krogan home world, Tuchanka, is one of the harshest in the Milky Way, honing the krogan into a physically powerful, aggressive, and adaptable species. Once considered heroes after the Rachni Wars, krogan expansion made them a threat to the galaxy until the turians and salarians used the controversial genophage to quell their numbers.
Several authorities questioned including the krogan in the Andromeda Initiative, given their history. Invitations were extended to several clans, particularly those who did not take part in the Krogan Rebellions, and their assistance eventually proved invaluable in building the Nexus. Colonist interviews show that many krogan see the Initiative as a chance to reinvent their people.
The krogan are considered a dying species in the Milky Way, as the genophage means only one in a thousand krogan pregnancies succeeds. In recent years, krogan have shown signs of adapting to the genophage, as they have to many other threats.