The same passage includes “the Necessary Existent, exalted”. Classical theological arguments hold that the Necessary Existent is uniquely one, so a second is ruled out by an independent metaphysical proof.
The important point is that the impossibility of another instance is established by reasoning outside the bare general form of the concept. This must not be confused with a proper name that simply identifies a particular person.
This is a theological and philosophical illustration whose premises belong to the tradition's metaphysical argument, rather than to the naming of an individual.