Rajiin claimed that, when she was very young, she was kidnapped from her homeworld and sold into slavery, adding that "There's a reason I was taken from my home. I have certain gifts." She also claimed that she didn't remember her homeworld or her family, but had had many owners in her lifetime. The last ship she lived on, she never left the cargo hold, "except for a few visits to the Captain's quarters."
In 2153, she was recruited by the Xindi-Reptilians to gather information on the Humans. She was placed in Zjod's sex slave shop in a floating bazaar on the Xanthan planet, where she conducted a staged escape. Captain Jonathan Archer, who was on the planet to obtain trellium-D, saved her and took her aboard Enterprise NX-01. When T'Pol discovered the location of her homeworld, Rajiin seemed apprehensive about returning, stating that "I don't remember much about it, and I doubt anyone there would remember me."
Aboard Enterprise, Rajiin used her telepathic powers to seduce members of the crew into a trance-like state, including Captain Archer, and presumably Hoshi Sato. During these encounters, she would illuminate the anatomy inside the other person's body by placing her hands near or on parts of the body she wanted to highlight, in order to acquire biometric data on them. After further attacking T'Pol, who resisted and suffered disruptions to her neocortex, Rajiin contacted her Reptilian handlers, stole a phase-pistol, but was eventually thrown in the brig.
When Archer noted the convenience of the timing of Rajiin's arrival and escape, he figured she was a plant of some sort. Although she apologized that she could not give him the information he requested of her, for fear of life, she did warn him that they were in danger. During this interrogation, two Xindi-Reptilian warships approached Enterprise, knocking the Earth ship out of warp before attempting to dock. During the fray, Rajiin finally explained to Archer that the Reptilians wanted information to build a bioweapon, but they required data about Humans before they could begin. After successfully boarding Enterprise and securing her release, they departed without further issues.
Afterward, she reported to the Xindi Council, who viewed the data she had acquired for use in developing a bio-weapon. She showed the councilors the scans she had taken by placing her hands atop the table in the Xindi Council chamber, which displayed the scans holographically above the table. Although the Reptilians were satisfied, Rajiin warned there was more to Humans than they knew, but Commander Dolim ordered her out of the Council chamber. (ENT: "Rajiin")
Later, when Archer and T'Pol time travelled to 2004 Detroit and discovered the Xindi-Reptilian bio-reactor, Archer recalled how Rajiin had warned them about a bio-weapon, before presuming what they had just found might be it. (ENT: "Carpenter Street")
In the final draft script of "Rajiin", the character of Rajiin was initially described as "a striking, humanoid female". The teleplay later stated, "There is something undeniably charming about Rajiin [....] She's very aware, and unashamed, of who she is." A scene description concerning Rajiin and Archer remarked, "There is something about her that he can't resist."
During the course of the episode "Rajiin", the character is shown in multiple different outfits and with slightly different hairstyles. A scene description in the script described the second look which Rajiin is shown with by stating, "[She] has cleaned up very nicely in fresh clothes." The third look Rajiin is portrayed in was described in the script as "a seductive outfit – her sleeping clothes" and a "stunning appearance."
Most of Rajiin's back-story is questionable; she may have been making at least part of it up to earn sympathy from Archer. The script provided an insight into her backstory by suggesting that, prior to her time aboard Enterprise, she might not have smiled in a long time. Regarding her powers, the script revealed, "Part of Rajiin's seductive power is the ability to block any memory of what she's done." Concerning her agility, the teleplay commented, "She's a highly-trained operative with extraordinary physical skill." In ultimately unused dialogue from the script, T'Pol clarified that Rajiin didn't read thoughts, despite using invasive telepathy, and that it was a more "physically invasive" form of telepathy than a mind meld.
Portraying the character
To adopt the role of Rajiin, Nikita Ager had to depict both the character's sensuality toward Captain Archer and members of his crew as well as Rajiin's duplicity as a spy for the Xindi-Reptilians. "I liked that the character, at least from what I gathered from it, had been on her own for so long that she had nerve," Ager recalled. "I was a little nervous about the sensuality, but I had to trust that I was in good hands there. I had to go with their knowing what they were doing." (Star Trek: Communicator issue 151, p. 46)
Nikita Ager was completely surprised but also very glad that, judging by the responses from fans of Star Trek: Enterprise, Rajiin turned out to be a character which energized the show's fan base by proving controversial. "From the fan mail I'm getting – and oh my goodness, you would not believe the fan mail that the show has sparked – I didn't know that they hadn't had an alien seductress like her before on Enterprise," Ager remarked, with a laugh. "Half the mail is, 'Wow!' People were so excited about a seductress who is an 'equal opportunity' seductress for the men and the women. And then I get letters from people saying, 'I can't believe Star Trek has gone there.'" (Star Trek: Communicator issue 151, p. 46)
In addition to being pleased with the episode "Rajiin", Nikita Ager was hopeful that she might return as Rajiin. "They left it so maybe Rajiin can come back," she observed. "I'm not sure that the captain and crew can embrace Rajiin after she wreaked the havoc she did. Maybe she's seen the light, and the Enterprise can embrace her. I don't know, but in any direction, I am excited and hopeful that Rajiin can come back." (Star Trek: Communicator issue 151, p. 46)