As familiars to Gara, they are extremely loyal to their creator and follow him without question. They are cheery and do not care about the outcomes of things whether it be for victims or their master.
The Bells collect desire for Gara through a game of chance where the victim is offered something like money or a way back to their own time. However to receive these offerings the victim would have to do something like keep their hair for the rest of their life or everyone would disappear, they also allow bargains. Should the person answer "yes" to the offer or bargain Cell Medals fly into Gara's device.