Good Video.
Good video. If they add the 0 AD period to the game, it will be a great challenge, although I imagine that many resources used for the Persians and Seleucids will be useful for them, although they should adapt it to the time period. The buildings should be similar to the Persians with some variations. The most complex part should be the civilization's characteristics, maybe they can reflect their different stages such as nomadic, expansion, and empire. Also, their diverse ethnicity reflected in the units they use, although I have found a lot of information about the composition of their armies. And I am sure they will have some technology or bonus like the Silk Road, bridge of two cultures, or trade with China, literally that benefited them a lot.