Marudashi and Morodashi
...souless, but with heart.....
two are some kind of helpers and work with Watanuki, aside the fact that they
guide shop visitors to their mistress, and also perform various other tasks.
Because they are souless bodies, they cannot leave Yuuko’s shop.
They are simply called Maru and Moro, but their full names are Marudashi and Morodashi (translation of both words is "exposing oneself in public"). When they speak, they often do it at the same time using the same words, and their ability to finish eachother’s sentences is uncanny.
Their deference comes in their looks: Maru is the one with her blue hair twisted and hanging from both side, while Moro is the one with the pink shorter hair with buns.
When a visitor comes to the shop, independent of where they are in the building, they react instantly and go to greet him/her, to lead them to Yuuko.
It’s never mentioned if she created them or not, but it’s her power that keeps them alive. I again will speculate of their existence, I personally think that those two are the store’s essence (like personification of the shop) and it’s Yuuko’s power who keeps them alive. I came to that conclusion reading one of the chapters when the girls appear one from the ceiling and one from the floor running in tears to Watanuki:
Watanuki, the master…! She said the shop will be okay now! She said she’d use the last of her power to keep it here! “The last”! The master’s really gone!!!
Chapter 183, pp. 9-10
So they even if they are souless, they have a deep connection to Yuuko and when she vanishes, they feel the loss, so much that they are able to shade tears.