This is an elephant archer. Most of the time, archers were used on top of elephants because its a lot easier than giving them a lance and telling them to use it effectively from that height. The riders are based on Indian military uniforms of the age, but the armor is something more typical to what the Greeks or Carthaginians might have used. This way it can be used for almost anybody, though its really meant for the Indians.
P.S. I'm going to make an Indian foot archer based on the archer here, but the tunic will be civ-specific, not white.