Warning: The following feature contains SPOILERS for Batwoman Season 2 Episode 2 "Prior Criminal History."
The second episode of Batwoman Season 2 ended with both Sophie Moore and Alice being knocked out by a woman named Tatiana. While little was revealed about this mysterious assassin, there is a chance that she is based on a Batman villain who went on to become an adversary of Kate Kane's version of Batwoman in the comics.
The final scenes of "Prior Criminal History" found Crows Security agent Sophie Moore going after Alice following Julia Pennyworth determining that Alice was hiding out in the abandoned Dresner Motor Plant. Foolishly, Sophie elected to go after Alice without backup and told Julia not to tell anyone else where she was going. While Sophie was able to confront Alice and the psychopath obliged her request to cuff her own hands behind her back, Sophie didn't notice that another woman had snuck up behind her until she suddenly had a katana blade at her throat. The woman said that Alice was hers, just before knocking Sophie out.
Alice recognized the woman, whom she identified as Tatiana, just after the woman remarked that Alice's latest stunt had earned her the wrath of the crime boss Safiyah Sohail. The stunt in question involved releasing bats infected with Safiyah's trademark Desert Rose toxin on Gotham City and then providing the antidote to Mary Hamilton, so a cure could be mass-produced in a hurry. A nonplussed Alice remarked that angering Safiyah had been the entire point of the exercise and that she wasn't afraid, reasoning that if Tatiana had been sent to kill her, "my head would already be in your carry-on (luggage), on the way back to Coryana." Tatiana agreed, saying that Alice would surely die for what she had done, before knocking Alice unconscious as well.
The CW announced in an earlier casting notice that Tatiana was the real name of an assassin known as The Whisper, who served as Safiyah Sohail's right hand. While there is no DC Comics character called The Whisper, there is a notable female assassin named Whisper A'Daire. A one-time student of League of Assassins leader Ra's Al Ghul, Whisper was given a serum that granted her immortality and shape-shifting powers. Though she was capable of assuming any identity, she favored taking on the form of a snake/human hybrid. She also possessed a hypnotic gaze and the power to spit an acidic venom. Whisper eventually left the League of Assassins and fell in with Intergang, where she became a member of the Religion of Crime and an enemy of Kate Kane.
It's unclear at this time if Tatiana possesses any of the powers Whisper A'Daire displayed in the comics or if she has a connection to the Arrowverse's version of the League of Assassins. It's possible that her nickname is just a coincidence and she doesn't have any connection at all to Whisper A'Daire or the Batwoman of the comics. In any case, anyone capable of taking the unpredictable Alice by surprise is not to be underestimated, even if they potentially have snake-themed superpowers.