u/Jewbacca1991

Personally i never managed to achieve that. Population is always on the decline by default.

When the first time you wiped a whole species, then what was your reason for it? And what kind of species you wiped?

For me i was playing collectivist fanatic spiritualist with a venerable ruler. I was waging multiple wars the other side of the galaxy, and an FE decided to attack me. With the other wars going on i had no way to win so i decided to take the least loss, and surrendered to the FE. Then they killed my starter ruler, and i decided to take revenge on them later.

Once i conquered them i checked their race, and pressed purge with extermination. Back in the day the collectivist had the ability to do that. I think the authoritarian should have it as well. It is meant to be a kind of empire where everything is for the Empire, and should a race deemed to be too inefficient, then it should be removed. Permanently.