With the advent of the series Star Trek: The Next Generation ( 1987 )— in which one of the main characters, Worf, was a Klingon — and successors, the language and various cultural aspects for the fictional species were expanded.

This retcon itself was later retconned, in Star Trek: Enterprise, via a storyline in which it is revealed that the original, quasi-human appearance of the Klingons is due to a genetic mutation caused by an engineered virus – as it happened, " genetic engineering " ( Chief O ' Brien ) and " viral mutation " ( Dr. Bashir ) had been the guesses Worf refused to confirm or deny.

The station's first appearance in Star Trek: The Next Generation was during the sixth season episode " Birthright " and in addition, two Next Generation characters, Miles O ' Brien and ( from Season 4 onwards ) Worf, became regular members of DS9.

Worf was at first not intended to be a regular character, since Gene Roddenberry wanted to avoid " retreads of characters or races featured prominently in the original Star Trek series ", and so the June 1, 1987 cast portrait did not include Worf.

In First Contact Worf is initially commanding USS Defiant before he is beamed aboard the Enterprise, while in Insurrection Picard jokes that Worf was late for his bridge shift due to being accustomed to life aboard Deep Space 9.

Worf was born in 2340 on the Klingon homeworld as the son of Mogh.

Although Worf was raised by humans, he considered himself a Klingon at heart and studied the ways of his people.

In 2364 Worf was assigned to the USS Enterprise-D as relief flight control and tactical officer with the rank of lieutenant junior grade ( TNG: " Encounter at Farpoint ").

Worf learned of Kurn's existence when Kurn was assigned to the Enterprise as an Exchange Officer.

When they and the Enterprise crew discovered that it was in fact Duras ' father that betrayed the Empire, Worf, realizing that the powerful House of Duras could not be publicly shamed without throwing the Empire into civil war, accepted a ritual discommendation from the Klingon High Council.

While Worf decided to accept this dishonor, it was decided to keep Kurn's true identity secret in order to protect his honor ( TNG: " Sins of the Father ").

K ' Ehleyr was eventually murdered by Duras when she found evidence of his involvement in the effort to discredit Worf.

Worf believed Gowron was the legitimate ruler and convinced his brother to bring forces loyal to him into battle on Gowron's behalf.

In 2369 while the Enterprise was at Deep Space Nine, Worf investigated a claim that his father might still be alive in a Romulan prison camp.

Worf was willing to consider the idea that Kahless was genuine because he believed the Klingons had lost their ways.

Worf learned that the Klingons were planning to invade Cardassia because of a coup which they had been led to believe was engineered by the Dominion.

Worf felt the war was wrong and he could not support it.

He felt that the ritual, which involved Worf killing him, was the only way to restore his honor.

After a year of war between the Federation and the Klingons, Worf joined a team sent to investigate claims that Gowron was a changeling in disguise.

Enraged, Worf claimed he lost only because he had been betrayed.

Incensed by such a violation of Klingon honor codes, Worf disregards Martok's request and confronts Gowron, who dismisses Worf's accusation and adds that his " child's uniform "-- referring to his Starfleet uniform -- is the only thing saving him from his true fate: a duel to the death ( to wit, his own.

( There is precedent for a Starfleet officer to not wear a regulation uniform, however: Deanna Troi in Star Trek: The Next Generation only wore regulation uniform during seasons six and seven ( followed by all the movies starring the TNG crew ), while Worf wore a Klingon sash with his uniform throughout his Starfleet career on both U. S. S Enterprises and Deep Space Nine but these series take place in later centuries than Star Trek: Enterprise ).

Indeed, during the first year of the Defiants commission at the station, she also serves as the ship's first officer, a situation that only alters upon the arrival of Lt Commander Worf, who assumes the role as the next most senior Starfleet officer of command grade.

Dr. Crusher summons Worf to inform him that he's the only person on the ship who is a compatible ribosome match for the Romulan.

Riker's only response is " Mr. Worf, fire.

While relieved that Nikolai is safe, Worf is concerned by what his brother has done and tells him that he has only postponed the deaths of the villagers.

The Council only accepted Duras ' charge of treason against Mogh believing that Worf would not challenge it.

K ' mpec, Picard, and Worf agree that the only course of action for Worf is to accept a discommendation, tantamount to admitting his father's guilt ; in exchange, the knowledge of the proceedings, including Kurn's true bloodlines, will be covered up.

Data determines that the only way to restore the realities is to send Worf via shuttlecraft to the Enterprise of his universe, passing through the fissure and using the shuttlecraft's engines to reseal it.

During their first meeting Worf and K ' Ehleyr have a heated argument, only barely managing to concentrate on the job at hand.

* A scene in this episode has Geordi La Forge strumming a lute ; Worf is behind him, cocking an ear, then suddenly snatches the lute from Geordi's hand and smashes it to pieces, offering only " Sorry " as an explanation.

When Keiko goes into labor, Worf is forced to deliver her child, though he is uncomfortable in the role of midwife and has only basic medical training.

The goal of this secret alliance is to destroy Picard and therefore Starfleet's only defense against the Borg but, despite his conditioning, Kirk is able to resist commands to kill Worf, Data, and Geordi La Forge, all of whom are attacked by him during his search for Picard.

The character Worf does so in almost every one of his appearances through two series and four films.

Worf would later reappear among the regular characters in Star Trek: Deep Space Nine ( 1993 ) and B ' Elanna Torres, a Klingon-human hybrid, would become a main character on Star Trek: Voyager ( 1995 ).

Worf, played by Michael Dorn, is a main character in Star Trek: The Next Generation and in seasons four to seven of Star Trek: Deep Space Nine.

Worf is the first Klingon main character to appear in Star Trek, and has appeared in more Star Trek franchise episodes than any other character.

Several " tall, slim, black actors " auditioned for Worf before Michael Dorn came along, walking into the audition in character and not smiling ( Indeed, Michael Dorn found the seriousness of the role, especially during the audition, at first to be uncomfortable, since he considers himself a comedian at heart ).

Worf is a popular character among fans.

During his confinement, Martok came to respect the indomitable character and fighting qualities of Worf.

He said: " When I got married my best man was Brent ( Spiner, who portrayed the ST: TNG character Lieutenant Commander Data ) and my groomsmen were Michael ( Dorn, Lieutenant Worf ) and Jonathan ( Frakes, Commander Riker ) and Patrick ( Stewart, Captain Picard ).

Later in the series, she becomes involved with the Klingon character Worf, and they marry during the sixth season of the show.

In the fourth season, Michael Dorn joins the cast of Deep Space Nine as the Klingon character Worf.

With the Klingons set to reappear, Berman suggested the return of a character from Star Trek: The Next Generation – the Klingon Worf – as a permanent officer aboard Deep Space Nine.

Dorn has appeared on-screen in more Star Trek episodes and movies as the same character than anyone else: he appeared in 175 episodes of Star Trek: The Next Generation, missing three: " Code of Honor ", " Haven " and " Shades of Gray ," 102 episodes of Deep Space Nine, missing four during his time on the show: " Rocks and Shoals ", " The Magnificent Ferengi ", " Chrysalis " and " Prodigal Daughter " and he also appeared in five Star Trek movies, bringing his total to 281 appearances as Worf.

Although never confirmed on screen, the character of Colonel Worf was intended to be the grandfather of Star Trek: The Next Generations Worf.

Dan Curry created the bat ' leth for Michael Dorn's Star Trek: The Next Generation character, Worf in 1990.

In 1995, he developed a smaller version of the bat ' leth, the " mek ' leth ", for Dorn to use when the Worf character was added to Star Trek: Deep Space Nine.

The role of Worf required a black actor in order to make the Klingon make up easier to apply, and was expected to be a recurring character, but following the casting of Michael Dorn and his work in " Encounter at Farpoint ", the role was expanded.

Worf also replaces the character of Christine Vale, the previous Head of Security who is a main character in the previous " A Time to " books.

In the TNG episode " Where Silence Has Lease " when Riker and Worf prepare to beam to the USS Yamato, Riker refers to him as a " lieutenant " and the character is wearing lieutenant collar pips.