There is many chief in the Southern Great Steppe in the past who declares that if they ever reach the Central Plains, they would burn all of their cities and kills all of the Yan people so that they would experience the pain, the screams and the despair of the innocent lives that the people of the Steppe had experienced before.
Not all tribes of the Great Steppe was combative against the Yan people in the past.
But Huo Qubing expedition and the Emperor Wu disregard of the people lives of the Great Steppe has instilled this hatred that will never disappear even after hundreds of years.
An Ashana once foretold, that one day, five great tribes would come down to the south and the people of Yan would face despair like they never felt before.
They would be enslaved and they would reap what they have sown. Hatred does not eradicate hatred.
Love eradicate hatred.
And since what Yan felt for other races is only hate, then hate would be their doom.