Uropater is a single entity, comprising a gestalt of illithid hiveminds. In a very real sense, the nation of Uropater is actually just a single organism. In a different sense though, it isn't.

Illithid live in communities, each of which has a sort of communal consciousness focused in an Elder Brain. That communal consciousness controls any given Mind Flayer, but each illithid is also separate and autonomous (like consciousness controls breathing). Uropater is formed in the same way of the collective unconscious of all the illithid communal minds. He can similarly override any given communal mind without effort. Focusing his attention on individual illithids is time consuming, difficult, and frustrating though (like learning to wiggle your ears, for each individual), so he rarely bothers.

Uropater would be a threat to all of his neighbors, but has been stuck in a full scale war with the Dreamsphere for the three decades since he came into existence. Note:Uropater was formed when three communal minds were coordinating a joint defense early in the war. This was not an expected result.

A note on gender and pronouns: Uropater has a distinct gender, but that gender does not translate from illithid telepathy to spoken language, and wouldn't be applicable at the individual scale. The emergent convention is to refer to Uropater as masculine. While this is technically wrong, it does have the advantage of consistency.