not sure about that archEXODUS.
i might be wrong since i haven't tested it as thoroughly as i'd like to, but from what i can tell Rally is just a modification to Divine Justice. it seems to work in the same way except that it only triggers when you kill a Demigod and the effect is different (heal over time and armor buff instead of instant health and mana). it also seems to affect the same area that Divine Justice does, which is something like a 20 unit radius centered on you.