There's really no need, but you can totally do it! Because enemies aren't necessary, nor is there a combat system to be balanced by number of Dessies, one can simply make an adventure where a single Dessy is born and has to discover the world on their own ^w^ But NPCs can also work! It all depends on what you want to play. NPCs can also be not-dessies, and just be other sentient things , like talking animals or other inanimate objects so really there's a lot of freedom there too if you want to have NPCs around~ As long as it's fun and silly, anything should be fair game tbh