This section is divided into two parts - Federation support characters and Spectra support characters. For ease of reference, these two parts are repeated in the Universe section.

Only named characters are listed, along with information about them from episodes and scripts. For instance, every Spectra Captain-of-the-day is not included here, since many of them were referred to as "Captain," "Commander" or simply, "you." For any information on unnamed characters, please turn to the individual episode entries.

Generally, this list is for characters that appeared in a single episode. However, certain characters like President Kane and Mala are listed here. While they did turn up in more than one episode, there really isn't enough background information about them to warrant lengthy individual character pages.

Turncoat characters against the Federation such as Donald Wade and Dr. Carig are still listed within the Federation section as they usually reject Spectra in the end. The end of the Federation listing also includes entries for named animal guests.

A special exception has been made for Captain Doom from Planet Urgos. He is the only villain to attack the Federation that had no affiliation with Spectra. However, he is included with Spectra since creating a whole new section for one character seemed kind of superfluous.

Many secondary characters were unnamed in episodes but were given names in episode scripts. These names are provided in these sections and noted as coming from scripts. Also, all character name spellings come from scripts. Voice actors for characters are given when easily identified or confirmed from sources like scripts, actors or other production personnel.