• Non-humans with a significant advantage over humans must also have a significant disadvantage that the mods judge to be fair. Ex The non-human is especially strong, but they are weak to loud sounds/high frequencies.
• Non-humans are not required to be humanoid, but expecting non-humans to become as technologically advanced as the humanoid species is unrealistic.
• You are allowed to have more than one species in your system, with the condition that you cannot use this to create an overpowered civilization by creating dozens of species solely with strengths that cover the weaknesses of other species.
• However 'neat' interspecies relationships are in a sci-fi roleplay, we aren't gonna make new species like that. For one, it can lead to selective breeding that enables a godmode species, and for another, gross.
• You can have an inorganic civilization, but it has to follow the same level of disadvantages that the regular non-humans have.