“Everything Ends. And So Our Story Begins.”

Eridian speculative biology time!

Erid is a very big planet, very very very big planet, twice the size of earth in fact- and divided by oceans, perfect conditions for populations to remain and develop separately and for long enough to create diferent species. So, unlike us, Eridians are a Polytypic genus: there's more than one species of sapient eridian, All of them sharing a common ancestor in the form of a small, 5 legged ambush-hunter land carnivore, all share common traits taking only slightly different evolutionary paths

Divers- get their name from living in semi-flooded caves, their high small vents allow them to be partially submerged without drowning and their long arms allow them to grip things easily underwater, similar to a sea-horse tail

Climbers- similarly, they get their name from their living enviroment, living in very high caves, their long thin arms allow them to grip and climb very steep rock walls, kinda like goats in a way

Drills and Stompers get their name from the shape of their arms, they both developed closer to the surface compared to the others, their arms are like that for dealing with sandstorms, while Drills "drill" themselfs in place, Stompers use their body weight to keep themselfs down

Blocks are very similar to Stompers, but they live in caves much deeper down, so they're quite compact

Common traits between all species: all Eridians can thrum, all Eridians organize in "colonies" like ants or termites (tho the specifics of how each colony works varies), all Eridians are True Carnivores(can only eat meat) and all Eridians are unisex

In theory any one eridian can procreate with any other eridian, between the 5 species there are 4 fertile hybrids and 3 infertile hybrids posible

note: tho each species has a more broad vague shared culture between themselves, none of them are a monolith, all of them have vastly different culture, language, texture, practices and even phenotypes between different colonies around the world

note 2: the fact humans are a monotypic species (there is only one in our genus) is really fucking weird to them