List of Babylon 5 characters  The list of "Babylon 5" characters contains characters from the entire "Babylon 5" universe. As the Babylon station was conceived as a political and cultural meeting place, one of the show's many themes is the cultural and social interaction between civilizations. There are five dominant civilizations represented on Babylon 5: humans, the Narn, the Centauri, the Minbari and the Vorlons; and several dozen less powerful ones. A number of the less powerful races make up the League of Non-Aligned Worlds, which assembled as a result of the Dilgar War, which occurred 30 years before the start of the series. Jeffrey Sinclair, played by actor Michael O'Hare, is the Commander of the Babylon 5 station in season 1. After one full season, O'Hare and series executive producer/creator J. Michael Straczynski made the mutual and amicable decision for the character and actor to depart as a regular. O'Hare subsequently reprised the character of Sinclair briefly in season two and a two-episode guest appearance in season three, enabling the show to wrap up loose ends. As a result of this departure, there are several minor inconsistencies between the first season and the remainder of the show, most visibly in "And the Sky Full of Stars" and "Babylon Squared". At O'Hare's personal request, the full reasons for his departure from the show were kept secret until after his death in 2012. The following year, Straczynski revealed that O'Hare struggled with delusions and paranoia due to mental illness, which ultimately prevented him from continuing to act. However, Straczynski emphasized that O'Hare's fans, particularly those of his role as Sinclair, had helped him cope with his struggle in ways medication never could. The character's backstory is given as having been born on Mars Colony. In an early episode of season one, Sinclair states that his family had been pilots "ever since the Battle of Britain" and Sinclair's father was a fighter pilot for EarthForce who participated in the Battle of Balos, the last engagement of the Dilgar Invasion. Sinclair continued the tradition and became a fighter pilot. Sinclair enlisted in EarthForce in 2237. During his time at EarthForce Academy, he met Catherine Sakai, with whom he had a relationship. After a year of living together, the two of them broke up, but continued to see each other off and on through 2258, when they became engaged.