Yameta

Yameta is a hamster living in a forest abode near The Mediator's house. He believes hamsters are the only intelligent creatures on Earth and aids The Mediator when she is shrunk down to the size of a fairy, even though she mocks his pride.

Yameta wages a losing war against the weasels of the forests and his home is overrun while The Mediator visits. In EX06, it's revealed he and his friends survived and started living under the floorboards of The Mediator's house.