The clash between the gods and their respective churches made it almost impossible for players that had no affiliation to participate. Players that are not affiliated with the churches that have their god descended are affected by spells cast even ally gods. Only members of their respective churches are immune to the damage of their respective gods.
The movements of mortals are also limited if they do not have any way of flight. The dragons could actively participate because they can fly. The presence of Basil, the Mother of Dragons, also empowers the dragons albeit not as powerful as a buff as a god does. Still, dragons are by far stronger than humans so that small buff compared to gods is still bigger since they have better stats overall.