Hell is a place without law or rights. Only the smartest and fittest creatures in this place own the privilage of living a comfortable afterlife.
Power is the ultimate charge of hell.
The ones with great power and many souls are being feared, respected and served.
To stay on top of the ranking, the most powerful demons try to make sure to stay as powerful as possible at all times. That requires special measures and methods.
Zuzu, one of the most powerful demons in hell, makes great use of her skills by owning a demon pet business. Auction winners and costumers of her products pay with souls they collected on their travels on earth. By having a business like this she makes sure the souls keep coming in for her without even having to travel and seduce humans herself.
Zuzu's girlfriends/pets PurPur and Milly are always involved in the events the business holds and proudly promote her upcoming guides, pet toys and merchandise. Their masochistic tendencies come in handy for ZuZu's business and their overall quality of afterlife. They sure are enjoying the privilages they have by being Mistress Zuzu's personal favourite pets.