Era

@Shkshkshk @rpg a big thing about aliens is that the concept works because there is only humans in our world, so they are true aliens to us. The moment there is diversity of intelligent species, the impact is lower in that aspect. I think that what you need to ask you is What makes this aliens and not just another specie that comes from somewhere else? What are the rules that are broken with their presence? What constitute their alterity? The answers to that will guide you to what you are after