The Ood are a humanoid species with coleoid tentacles on the lower portions of their faces. In the distant future, the Ood are a slave race to humanity, performing menial tasks, and it is claimed that every human has an Ood servant.

The Ood offer themselves for servitude willingly, having no goals of their own except to be given orders and to serve. It is also claimed that they cannot look after themselves, and if they do not receive orders, they pine away and die. However, mention is made of a group called the "Friends of the Ood" who are apparently lobbying for Ood freedom.

The Ood require a translator device, a small sphere connected to their "mouths" by a tube, to facilitate speech between them and humans. There appears to be no gender differentiation among the Ood, and they say they require no names or titles as they are "one", but they do have designations such as "Ood 1 Alpha 1".