Nope it was the Parthians who had the large empire, the Saka just nabbed a city from them and they've been unable to take it back due to pressure from the AS, can't remember but i think Baktria is also involved too.

The interesting expansion for me is the Sauromatae's drive into central europe, there's every chance of them clashing with rome or the celts if the rebel superstacks are defeated.