Warning: SPOILERS for Batwoman season 2, episode 3, "Bat Girl Magic!"
Safiyah Sohai made her first on-screen appearance on Batwoman, claiming to have kidnapped Kate Kane, but giving no reason for why she did so. One possibility is that the notorious pirate queen has developed a crush on the activist heiress and her abduction plot is all part of a convoluted seduction ploy.
While Safiyah did not appear in the flesh until Batwoman season 2, episode 3, "Bat Girl Magic!" she has been a presence on the show for some time. Her name was mentioned throughout Batwoman season 1, usually in connection to the mysterious past of the villain Alice. It became clear near the end of the series' freshman season that Safiyah was being built up as a major threat and she was later confirmed to be one of the chief villains of Batwoman season 2.
It's impossible to guess what the plans for Safiyah might have been before Ruby Rose left the series and it was decided to replace Kate Kane with Ryan Wilder rather than recast her. It seems likely, however, the show would have attempted to recreate the romance that bloomed between Safiyah and Kate in the original Batwoman comics. Given that, it's entirely possible Batwoman's writers may have attempted to push the same storyline despite Rose's absence, but take it in a darker and more demented direction, establishing Safiyah as a stalker with a crush on Kate Kane.
Safiyah and Kate's Romance In The Comics
Safiyah Sohai was introduced in the 2017 Batwoman: Rebirth series, through a series of flashbacks detailing what Kate Kane referred to as "the lost year." Shortly after being outed and expelled from West Point Academy, Kate fell into an alcohol-induced downward spiral and fell off her yacht. Kate washed up on the shores of the pirate nation of Coryana, where she was taken in by the so-called "Mother of Warlords," who acted as a balancing force between the various outlaws who used Coryana as a base of operations. Her underlings assumed Safiyah intended to ransom Kate, but the pirate queen soon found herself bewitched by "her siren" and Kate returned her affections, finding a freedom as Safiyah's beloved that she never had in her old life.
This did not sit well with Safiyah's former favorite, a woman named Tahani whom Safiyah had trained in the art of war before taking her as a lover. Tahani attempted to kill Kate during Kate's first mission as a raider of Coryana, after Kate insisted she be allowed to pull her own weight and be more than just a pretty pet. That, coupled with the realization that Safiyah had killed one of her own men instead of Kate after blaming him for a plague that had begun killing the island's population of foxes, spurred Kate to leave Safiyah behind her and set out on the path that eventually led to her becoming Batwoman.
Safiyah's Role In Batwoman Season 1
No relationship, romantic or otherwise, existed between the Arrowverse versions of Kate Kane and Safiyah Sohai, and Kate denied having ever heard of Safiyah when Julia Pennyworth first mentioned her name. Safiyah was still a major presence during Batwoman season 1, having been responsible for sending an assassin called The Rifle to Gotham City to acquire a gun capable of penetrating Batwoman's armor. She was also apparently responsible for killing the Wonderland Gang after Alice disabled the gun in question and arranged the deaths of the only people on Earth capable of repairing it. Later, Safiyah was revealed to have made a deal with Julia Pennyworth to give up on pursuing a weapon to destroy Batwoman in exchange for the journal of Lucius Fox; a bargain Julia backed out of when she learned the journal contained the secret of how to pierce Batwoman's armor. This resulted in Safiyah sending someone to stalk Julia and her then girlfriend Sophie Moore, sending Julia photos of the two women to let her know they were being watched.
Safiyah's Story In "Bat Girl Magic!"
The Batwoman season 2 premiere ended with Alice being delivered a message, apparently from Safiyah, claiming credit for the plane accident that killed Kate Kane. This pushed Alice to enact her own mad scheme to poison the people of Gotham City with Safiyah's trademark toxin and then offer the antidote to Mary Hamilton, who arranged to have it mass-produced. The plan got Safiyah's attention and earned Alice an audience with the pirate queen, who arranged for Alice to be brought to her at her home in Coryana in the episode "Bat Girl Magic!"
To Alice's surprise, Safiyah denied any involvement in the plane accident and the deaths of the Wonderland gang. Indeed, Safiyah claimed that she hadn't thought about Alice or her sister since she left Coryana, revealing that Alice had been one of her students. Safiyah also seemed to be ignorant of the bargain Alice had made with The Rifle in Batwoman season 1, which led to Alice acquiring the Desert Rose toxin. The practical upshot was that Safiyah had been content to leave Alice alone and believed that a third party was trying to pit the former allies against each other.
Alice didn't believe a word of Safiyah's story until she showed Alice Kate Kane's distinctive garnet necklace, which was twin to Alice's own necklace; a gift both sisters had received at their Bat Mitzvah. Safiyah pointed out it would have been impossible for her to have that necklace if she had blown up Kate's plane while she was inside it and that she had no intention of killing Kate. By the episode's end, Safiyah had promised to release Kate into Alice's custody in exchange for her completing a task that was named off-camera.
Why Safiyah Might Be Interested In Kate
There is little about Safiyah's story in "Bat Girl Magic!" that makes sense. She claimed not to have thought of Alice or Kate in years, yet clearly undertook a plan to kidnap Kate before she took her doomed flight back to Gotham. It also seems highly unlikely from what has been shown of Safiyah's operations that The Rifle would have been allowed to leave Coryana with the Desert Rose without her knowledge or permission. In the end, there is little of Safiyah's story that she and Alice have a common enemy that can be verified independently. The only thing that makes the story halfway plausible is that the alternative was for Safiyah to have fabricated a perfect replica of Kate and Alice's twin necklaces to make Alice believe Kate was in Safiyah's custody. While this is possible given Safiyah's resources, there are far easier ways to bring Alice back into her service if there was a task only Alice could accomplish. This begs the question; why go through all this trouble to kidnap Kate Kane in the first place?
The answer may lie in two separate scenes in "Bat Girl Magic!" In the first scene, the assassin Tatiana (who had been established as Safiayh's right-hand woman and lover) attacked Sophie Moore after she refused to allow Alice to wander Gotham freely in accordance with Safiyah's wishes. The fight was later broken up by Safiyah, who commented that saw what Julia Pennyworth had seen in Sophie, who was able to hold her own against Tatiana with her hands bound. Later, after Sophie and Alice were returned to Gotham, Sophie wondered out-loud why she was still alive. Alice replied that it probably wasn't a good thing, "because Safiyah spared you, which means she has a crush on you, which is all very well and good, until it's not."
In the comics, Safiyah Sohai was the sort of woman who would not let anything stand in the way of her pursuing her heart's desires, even at the risk of her underlings' loyalty. The Arrowverse version of Safiyah seems to be cut from a similar cloth, based on Tatiana's reactions to Alice and Alice's reactions to Sophie being spared. It seems that Safiyah, who had conversed with Julia Pennyworth off-camera, wanted to see Sophie in action for herself, clearly having a thing for warrior women. This could also explain why she abducted Kate Kane, as it seems more than likely that Safiyah has deduced Batwoman's secret identity.
It's unclear if the writers of Batwoman had originally planned to play out the romance between Safiyah and Kate (either in flashback or as a subplot of season 2) before Ruby Rose left the series. It does not seem impossible, however, that Safiyah's motivation for kidnapping Kate Kane might have involved giving herself a chance at romance rather than seeking revenge on Alice. At the very least, it's likely she may attempt to woo Kate off-camera, leading to the possibility that Kate might not want to leave Coryana even after Alice accomplishes whatever task Safiyah assigned to her.