In aware stage during mid or late game there could be a possibility in which some npc members of your species branch off into another kind of species to either fill an ecological niche or adapt to a different habitat.for example Most of the finches of the Galapagos evolved from a common ancestor and now they all look similar except for different beaks. A more radical example is that tortoises have evolved for land while sea turtles evolved for the sea. The chance of you meeting a close relative obviously has to do with how successful your species is.You also might have to be in an ecosystem with a few empty niches but due to procedural evolution another creature that's unrelated to you might fill that niche up
In order to survive, you must look to the stars for an answer.
It's such a good idea that it's been part of the plan since forever Serious answer: you would have to go into more detail if you want to propose something different from what we have planned. For what we have planned, see the GDD (I think) or the DEV forum (I think) or the subreddit (I think). I'm heading out right now but I can try to find you something where we discussed this previously when I return.