Forgottenwrites
In this world of Warriors, Twolegs had eventually died out and left ruins of their own buildings. The kittypets either stayed in their homes, turning into loners or grouped rouges, or just adventuring outward. Most were denied entry to the Clans. The Clans felt shocked, but quickly moved on from their extinction, feeling a little more safe. Prey became more bountiful over time, but eventually stopped at a certain point and maintained a safe level. Nature overtook any places the twolegs had once bustled and lived. Of course, other problems aren't stopped from occurring such as foxes or any other large creatures, but not much else.