Purple Kingdom is, as its name says, a kingdom where the most common color is purple.

One of the safest and most organized areas of Deep Imagination, everyone tends to be respectful.

It is a large kingdom, where Rio can see what the Creations' lives are like without worrying about being attacked at all times.

It has hotels, theaters, several houses and some shops.

Exploring a lot, Rio can notice signs mentioning names that seem to be important, such as:
"Katie stop picking fruits that are not yours"
"Bugora this area is prohibited explosives"
"Due to the partnership with Grasity this area is only for her seeds"

Subareas:

Purple Castle:

Replaces the home (or whatever was Toriel's house called, I legit forgot.)

A considerably large castle.

Exploring enough, it is possible to see notes from the queen and how she seems to be very focused on impressing the Creator.

You can also find a drawing of what she imagines Rio would be like, the drawing doesn't quite get it right.

Creation Prison:

Just a generic prison for Madsune to be introduced at.