Some progress!
Obligatory landing in an Isekai world and meeting a monster buddy scene done. I think I'm going to take a queue out of the slime anime. The game is going to revolve a lot around a sky city of humans and the history leading up to this is going to be somewhat reminscent of CoD. There's going to be flying human cities with most monsters living wild on the surface. The difference is that you are going to be aligned with the wild monsters at least at first. You'll be taking over the ruins of an old transport hub that's been occupied by smugglers and trying to turn it into the first monster city. Primarily by taking mates and having babies. There's going to be a lot more breeding content in this and it's going to be present right from the start.
The premise is that the human skycities particularly this one are starting to run out of resources as they've been cut off from the surface. By taking over the depot and making use of the unique abilities of your girls and their progeny you'll be building up both your settlement and supporting theirs. You'll be dealing with extreme anti monster prejudice. But also be essential for their survival which will create tension. Especially when your efforts slowly start to actually win people over.
Talking about the primary antagonist and threat would be a little .. spoilery. But that's what tags are for.