Star Trekhas brought joy and amazement to fans for decades. The franchise’s pinnacle may have been in the 90s, a decade that saw three different series on the airwaves. While two of these series focused on space travel,Star Trek: Deep Space Nineshifted focus to a space station. This new setting, coupled with the darker tone, changed up the franchise’s formula in more ways than one.

Having threeStar Trekseries on the air during the decade presented the opportunity for crossovers between the series. Using alternate dimensions and time travel,Deep Space Ninecharacters found their way on to one of the other series. Plus, modernStar Trekhas found a way to bring back classic characters.

Alexander Siddig as Julian Bashir

5Julian Bashir: The Next Generation

The starship Enterprise docked at theDeep Space Ninespace station setting up this crossover in the episode “Birthright Part 1.” In the episode, Data has a dream-like experience after an accident, and it causes him to hallucinate about his creator. While searching for the meaning behind this dream, Data turns to some help from both the Enterprise and Deep Space Nine crews.

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Julian Bashir is the Chief Medical Officer on board the space station, so Data works with Bashir and Geordi La Forge to recreate the circumstances that led to his dream. Both Bashir and Geordi are reluctant but still help Data with his experiment. This was Bashir’s only appearance on the otherStar Trekprogram.

4Quark: The Next Generation, Voyager, Lower Decks

Quark has the widest range of crossovers of anyDeep Space Ninecharacter, appearing in three other series. He makes a very brief cameo inThe Next Generationin the episode “Firstborn,” providing information to Riker. Quark also appears in “Birthright Part 1,” the same episode that featured Julian Bashir. Finally, he briefly appears onVoyagerin the series premiere, “Caretaker.” The Voyager is leaving from Deep Space Nine, and Quark appears at the beginning of the episode attempting to swindle the naive Harry Kim.

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Quark makes his animated debut in the seriesLower Decks.In the episode “Hear All, Trust Nothing,” the crew of the Cerritos is docked at Deep Space Nine, and Lower Decks crew members stop by Quark’s bar. It’s revealed that Quark stole parts for his replicators, and a deal must be reached for the alien whose parts were stolen to get part of Quark’s profits.

3Morn: The Next Generation, Voyager, Lower Decks

Alongside Quark, Morn makes an appearance in the same episodes ofVoyagerandLower Decks,since he frequents Quark’s bar. He also has a cameo inThe Next Generation. Morn was always a popular background character onDeep Space Nine, often seen in the background of scenes in Quark’s bar. He continued this tradition in his appearances on other series.

These appearances putMorn in the companyof Quark, Picard, Riker, Troi, Kang, and Q, who all appeared in multiple series across the franchise.

Quark (Armin Shimerman) holding two bars of gold-pressed latinum, smiling greedily. Image source: WhatCulture.com

2Kira Nerys: Lower Decks

Following the series finale ofDeep Space Nine, Colonel Kira Nerys took over the space station. That continues in her appearance in theLower Decksepisode"Hear All, Trust Nothing." She appears in the episode giving the bridge crew of the Cerritos a tour around the space station, while the Lower Decks crew are on their own journeys and visiting Quark’s bar.

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Morn

It’s through Kira thatDeep Space Ninefans get the Easter eggs back to the series they love so dearly. Kira shows off Sisko’s baseball, letting fans know she is still awaiting his return, and is ready to hand the office back over to the Captain who commanded the station for years. While Quark’s appearance could have been the plot to any episode featuring the Ferengi, and Morn sat in the background like he always does, Kira’s appearance carries the torch for the rest of theDeep Space Ninecrew.

1Worf: The Next Generation, Picard

Michael Dorn has the most single appearances inStar Trekhistory, so it makes sense that his character,Worf, would have multiple crossover appearancesin some of the wildest ways possible. Worf started as a crew member aboard the starship Enterprise duringThe Next Generation. The Klingon rose through the ranks on the bridge crew, becoming the security officer following the death of Tasha Yar. He was an important member of the crew for all seven seasons before leaving the Enterprise to join the Deep Space Nine crew after Enterprise was decommissioned.

Worf would also appear in all four films featuringThe Next Generationcrew. While those appearances have raised some questions about continuity, his appearance inNemesisaddressed his fate afterDeep Space Nine, where he was returning to Starfleet after serving time as a Klingon ambassador. Worf would also make appearances in seasonthree ofPicard. He appears as a member of Section 31 who is now Rafi’s handler. He works with her to uncover the Borg’s plans and then works with his former crew to stop the Borg and save the United Federation of Planets, again.

kira-nerys ds9

Worf in Star Trek: Deep Space Nine.