Oranos' speed bonus is the answer, and turmae are the units, yes. With Oranos they are just as fast as hippikons. Melee raiders need to get into melee contact before attacking. When the villies run away, the melee raiders must chase and can only pull off a hit now and then. On top of that, melee raiders disperse their damage across the villies (because it is more than hard to have them all attack the same villie because they would all need skin contact to that villie first), so it lasts longer before the first villie dies.
Turmae, however, can all focus fire on one villie (so that one is immediately dead for good). Then they run a little bit behind the fleeing villies in order to catch up and fire again. No need to overtake the villies and block them so that you get time to get your raiders into melee range and deliver enough damage for a kill.
They can also attack from outside range of the defensive tower that would protect the villies against melee raiders. They are not vulnerable to the +100% tower bonus from the crennelations upgrade (although crennelations will help to hit them better). They still have good pierce armor against the towers. They can attack from behind the forest that your villies are hacking at (or any other obstacles). And still they are fast enough to run if superior opposition shows up.
Sky passages are good in theory, but rarely seen in 1v1 RM games because they are expensive, require a slow citizen at the desired dropoff-point and require some micro to operate. Things may be different in team games though.
Darkness is a state of mind
Valor is the contempt of Death and Pain. (Tacitus)
Problems worthy of attack prove their worth by hitting back. (Piet Hein)