"It's a letter of the alphabet, as far as I know."
The Q were a seemingly omnipotent and immortal species who inhabited the Q Continuum, possessing the ability of instantaneous matter-energy transformation and teleportation, as well as the ability of time travel. The Q had control over space, time, matter, and energy. (VOY: "Q2") In addition, Q spectacularly claimed to possess an IQ of 2005. (TNG: "Deja Q") They didn't make official contact with the Federation until 2364, when the crew of the USS Enterprise-D met Q. (TNG: "Encounter at Farpoint") At least one Q, acting on his own, had intervened and influenced Human affairs since at least the time of Isaac Newton. (VOY: "Death Wish") Their society was also referred to as the Q Continuum, or simply "the Continuum".
The Q evolved over countless centuries into their current form and considered themselves to be the ultimate form of evolution, existing in a state of "ultimate purity". However, this caused most of the Q to develop an apathetic attitude towards the universe, as the Q believed that they already done everything and had experienced everything. As such, there was nothing left for them to see, do, experience, or discuss, because they had already done so at some point. (VOY: "Death Wish") The exact circumstances of how the Q came to exist is unclear. While Quinn stated that the Q were once not unlike humanoid lifeforms, Q implied that the Q never came in to existence, but rather always were. (VOY: "The Q and the Grey")
The true extent of the abilities of the Q is somewhat unclear. While most Q claimed to be omnipotent, and at least one Q claimed they were all-knowing, there is some reason to dispute these claims. Quinn implied that the Q were not completely omnipotent. Considering that Quinn was a dissident, his claims may not have been entirely accurate, though they were supported by the fact that Q could be killed, which if they were completely omnipotent, would not be possible. (VOY: "Death Wish"; TNG: "True Q") At one point Q indicated that Humans might have one day equaled his species. This concern was, in fact, one reason which the Q wished to learn more about humanity, implying that they were ignorant regarding this aspect of the future. (TNG: "Hide and Q") However, what is evident is that their capabilities reached cosmic levels of power. An individual Q could accomplish such feats as traveling to a time and place that existed before and outside the universe itself, accidentally destroy a galaxy, or changing the gravitational constant of the universe, all on a whim. (TNG: "Deja Q"; VOY: "Death Wish"; TNG: "True Q") One thing which Q normally did not do was mate with another Q. When Kathryn Janeway suggested the idea, Q stated flatly that even if he wanted to mate, that he would not know how, as it was totally unprecedented. Janeway replied that he would figure it out, being omnipotent, after all. (VOY: "The Q and the Grey")
An aspect of 24th century interactions with the Q included involvement in a Q Civil War. The Q had come to fear the influence of Human compassion and curiosity into their otherwise timeless, apathetic, and stable culture. The war was incredibly destructive to this dimension and involved weapons which, during a firefight, incidentally caused the supernova of numerous stars. The war was ultimately ended upon the birth of Q Junior, restoring the Continuum to the status quo. (VOY: "The Q and the Grey")
The Qs' abilities were not only limited to members of the Q Continuum species, as William T. Riker was once bestowed with the powers of the Q. (TNG: "Hide and Q") The Continuum had the ability to overpower and remove the powers of any individual Q without their knowledge, which was usually revealed to the Q in question when they were unable to use them, although they did retain their full intellect. This was usually used as a form of punishment. (TNG: "Deja Q"; VOY: "Q2")
- Q (female)
- Q (Junior)
- Q (Colonel)
- Q (Judge)
- Quinn (formerly)
- Amanda Rogers
- William T. Riker (temporarily)
In the Peter David novel Q-Squared, Trelane was revealed to be a member of the Q Continuum, with Q being assigned as his mentor. In the book, Trelane was able to tap into "The Heart of The Storm," the theoretical and literal center of the universe, where chaos exists; doing so gave Trelane more power than the entire Continuum, allowing him to close it off and play with the universe as he pleased. Trelane then manipulated three different tracks of the Enterprise-D timeline, with the ultimate goal of the experiment being the merging of all parallel timelines and the destruction of the multiverse order. Captain Picard, with the help of Q, managed to stop Trelane, though the experience reduced Trelane to a speck of his former existence.
The trilogy Q Continuum introduced an additional Q known as the Quaestor, who resembled Picard. In this series it was revealed that the most prominent Q pulled a similar being known as 0 through the Guardian of Forever, and that 0 proceeded to bring forth such entities as the "God" of Sha Ka Ree, Gorgan, and the Beta XII-A entity to join him in his villainy. The Continuum was forced to act, with the Quaestor leading Quinn, Q2, and the female Q into battle against 0 and his forces. The outcome of this battle was the imprisonment of the Sha Ka Ree entity at the center of the galaxy and 0 outside of it, while their two allies escaped. The Q Continuum created barriers to prevent the return of their two prisoners, and Q was assigned to watch over Earth due to his part in wiping out the dinosaurs by redirecting an attack aimed at the female Q by 0. The barriers created to keep 0 out were later weakened by the Q civil war, and he briefly managed to return but was then defeated by the unlikely alliance of Q and the Calamarain. He was then returned to exile, and the Continuum repaired the barriers.
The Q Gambit featured the Q caught in a war against the Pah-wraiths. Unlike the three-dimensional world, they found themselves oddly powerless in their own continuum. Following Q's merging with a Prophet, he became even more powerful than he had been before.