In 2375, Cretak was a firm supporter of the Romulans' alliance with the Federation and the Klingons against the Dominion. She further took an active role and served as the Romulan representative to Deep Space 9. In this capacity, she worked directly with Admiral Ross, Captain Sisko, and Colonel Kira to coordinate fleet deployment and maintenance of Romulan forces in the area. (DS9: "Image in the Sand", "Shadows and Symbols", "Inter Arma Enim Silent Leges")
Cretak would develop a cordial working relationship with Kira, however, Cretak also authorized the Romulan fortification of Derna against the Bajorans' wishes, because she believed it was in the best interests of the Romulan people, under the guise of a hospital. While Ross supported her initially, she later rescinded her decision during a standoff between Romulan and Bajoran forces led by Kira when she met Starfleet opposition. (DS9: "Image in the Sand", "Shadows and Symbols")
Cretak was not without complaints to the Alliance. She once complained that Klingon forces were higher priority than Romulan warbirds for maintenance. She met resistance from Worf and General Martok when they made the argument that they fight more vigorously, though she viewed it as reckless.
Cretak later attended a conference on Romulus in which several topics were to be discussed about Dominion technology, with Doctor Julian Bashir as a featured speaker. During this conference, she would be the victim of a Federation Section 31 plot to put Chairman Koval, who was informing Section 31, on a seat in the Continuing Committee, a seat for which she herself was in competition. Bashir, who was also unaware of the plot, approached her, believing a secret Romulan Section 31 operative planned to assassinate Koval. To thwart it, Bashir asked her to search Koval's personal database for Luther Sloan's possible accomplices, to which Cretak reluctantly agreed. She was arrested while attempting to access the files, and brought before the Committee. Despite her honesty in front of the Committee, and Bashir's corroboration, Koval brought Sloan in as a witness and argued Cretak was part of the plot, forcing her to accept that even if she wasn't part of the plot she would still be a fool who had been manipulated by a Starfleet Intelligence agent into committing treason and accessing secured files. The Committee agreed and found Cretak guilty of treason, dismissing her from the Senate as well as postponing her sentencing to a later date.
Admiral William Ross later justified his complicity in Cretak's downfall by noting that she was a "patriot" who would recommend that the Romulans pursue a separate peace with the Dominion if she believed it was to her people's advantage. According to Admiral Ross, after being dismissed from the Senate, Cretak would most likely be imprisoned, and possibly executed. (DS9: "Inter Arma Enim Silent Leges")
"My people have a reputation for arrogance. I'm afraid it's well earned."
"But you're different. Or so Admiral Ross tells me."
"The admiral and I have a good working relationship. I hope to have a similar one with you."
"I'd like nothing more."
"I had no idea Bajorans were so efficient."
"Coming from a Romulan, that's quite a compliment."
"You can talk about compromise all you want. Any ship attempting to break through that blockade will be fired on."
"Colonel, do you seriously believe that your antiquated collection of impulse ships stand a chance against our warbirds?"
"We'll find out soon enough, won't we? End transmission."
"You still think she's going to back down?"
"She has to, because I won't."
- - William Ross and Kimara Cretak, of Kira Nerys during the Derna crisis (DS9: "Shadows and Symbols")
"Don't tell me this is your first glass of Romulan ale."
"Well, it was illegal."
"That never stopped most of your colleagues."
Cretak was played by actress Megan Cole in "Image in the Sand" and "Shadows and Symbols", and Adrienne Barbeau in "Inter Arma Enim Silent Leges". The character is one of three full-blooded Romulans in the Star Trek franchise to receive a first name, the others being Admiral Alidar Jarok and Doctor Telek R'Mor.
According to the PADD that Kira reads in "Image in the Sand", Cretak was involved in the events of the Star Trek: The Next Generation episodes "Unification I" and "Unification II". For more information, see the discussion page.
Due to other commitments, Cole was unavailable to reprise her role for "Inter Arma Enim Silent Leges" so the producers chose Adrienne Barbeau instead. As Director David Livingston noted, it was a good choice; "She'd been in before to read for Star Trek, and this time she nailed the part. She brought a lot of humanity to it, which made Cretak a very rich character. She had the strength of a Romulan but a great deal of emotional depth." Writer Ronald D. Moore agreed; "Adrienne was great. She brought something different to the role, a certain sympathy and vulnerability that worked for the character in this episode. You wanted to like Cretak more in this than you had in the other two [episodes]. And that made you feel bad she was going down at the end. Cretak was much harder in the two-parter because she was there to serve a different purpose. She hadn't been designed with [Inter Arma…] in mind." (Star Trek: Deep Space Nine Companion, p.661)
In his review of "Image in the Sand", Star Trek author Keith R.A. DeCandido didn't enjoy Cole's performance as Cretak, "Megan Cole has all the charisma of a dead fish – the bland affect that made her an effective bureaucrat in "The Outcast" served to make her a spectacularly uninteresting Romulan. As a result, her heel-turn from friendly to militant has no bite to it."  Though in his review of "Inter Arma Enim Silent Leges", he thought Adrienne Barbeau, "…brings much more nuance to the role of Cretak than Megan Cole’s bland delivery could manage." 
Barbeau found her audition for the role a difficult one due to the dialog being very technical but she was glad to have been offered the part. "Everybody was lovely. I think I knew Rene [Auberjonois] before that, but if I didn’t, we became fast friends. Alexander Siddig was wonderful, too. I loved working with everybody." she recalled, in a 2013 interview. Her first day on set started at 4:30am for makeup which consisted of a wig and some airbrushing. "It seems to me that it went on very easily." Barbeau said, "I don’t remember how easily it came off, but I don’t remember any pain or suffering getting it on."  Michael Westmore designed the makeup for Cretak. 
Megan Cole's long-sleeved, gray/olive-colored costume with square pattern and black piping, as seen in "Shadows and Symbols", was later sold off in the It's A Wrap! sale and auction for $965.00 , while Adrienne Barbeau's light brown dress costume featuring multi-colored stripes, and a dark brown dress with raised wave/diamond pattern, both worn in "Inter Arma Enim Silent Leges", were also sold off for $609.00 and $810.00, respectively. All three of the character's costumes feature a cast-resin grey pin-backed badge identifying her as a member of the Romulan Senate.  
The Star Trek: The Lost Era novel Catalyst of Sorrows states Cretak had a cousin called Taymor and another family member called Kaitek, and is in a relationship with Koval as of 2360. The novel also recalls how Cretak attended the Khitomer Conference in 2293, where she met Nyota Uhura, with whom she stayed in contact over the following sixty years.
Cretak also appears in the Tales of the Dominion War short story "Blood Sacrifice" which takes place immediately before and during the events of "In the Pale Moonlight", in 2374. During a conversation between Cretak, Ambassador Spock, and two of the story's characters Ruanek and Amarik, Cretak learns of Senator Vreenak's death.
Several weeks later, as written in the Pocket DS9 novel Hollow Men, Cretak attends a conference on Earth where she meets Admiral Ross for the first time, marking the start of their close professional relationship.
Following the events of "Inter Arma Enim Silent Leges", the Star Trek: Vulcan's Soul novel Epiphany reveals that the Federation launched an unsuccessful protest in response to Cretak's sentence. Two years later, Cretak disappears from her prison cell, with Neral suspecting the involvement of Romulan military officer Liviana Charvanek. It also reveals that Praetor Neral had high hopes for Cretak.
Cretak also has a card in the Star Trek Customizable Card Game which features Adrienne Barbeau's portrayal of the character.