So I'm running a mythic game where the PCs' end goal is to become the new dominant Pantheon of Earth. Or at least of their region of it. As a young godling, one of the players wants to create new species in game. I'm fine with that, but I feel like just saying "sure you can make a new species, whatevs" would be too easy.
I'm thinking that I might make it so that he has to have 'craft construct' as a pre-req, sort of as a 'You have to know how to make something that's independently animated' kind of thing. Other than than that, though, I have no idea as to what sorts of things I could / should put into this, in regards to how powerful the species can be, how much it costs or if they can simply convert an existing species into a new one and make that cost less than making a new species wholesale.
Any thoughts?
This is third-party, but it's basically what you want.
This really reminds me of The Chronicles of Amber. Characters in that book series essentially raise armies of perfectly suited monster-men to fight each other (through dimension hopping and probability manipulation).
I am going to have to say that this comes at the very end of the mythic path, right? Can't you make it like a mythic capstone for certain mythic paths (like the godly and wizardly ones and maybe the warlord-y one)? Requiring craft construct might be more requirement than you want. That would be a 4-feat chain: Craft Magic Arms and Armor, Craft Wondrous Item, Craft Construct, and then you new feat. That will also require caster level 5.
Frankly, you should think about how easy you want the power to be and also think about how powerful the ability is. Can the characters control this new race? How many will there be?
Maybe you can just make it like the leadership feat, but all the characters the feat grants grant are from the new race that the character creates using--perhaps--using up to RP15.