Stheno

Stheno was a snake who was held captive and forced to perform as part of a Maledictus attraction at the Circus Arcanus in 1927. She was one of several snakes who shared an enclosure with Nagini, a Maledictus, and could communicate with her through Parseltongue. Stheno's existence is known only from the events depicted in the Fantastic Beasts film series (Fantastic Beasts: The Crimes of Grindelwald - The Original Screenplay).

In 1927, Stheno lived in a snake pit at the Circus Arcanus in Paris, France. She and other snakes were part of the act featuring Nagini, who would transform from a woman into a snake before a live audience. The circus ringmaster, Skender, would often taunt and poke the snakes with a hook to make them hiss aggressively, adding to the spectacle. Stheno was present when Nagini expressed her weariness with their captivity and her fear of the day her transformation would become permanent. Stheno advised Nagini to be careful, as Skender was watching them. Her fate after Nagini escaped the circus with Credence Barebone is unknown (Fantastic Beasts: The Crimes of Grindelwald - The Original Screenplay).

Stheno's specific species or physical appearance is not described in detail. She is depicted as one of several languid snakes sharing an enclosure. Her personality appears to be cautious and aware of her surroundings. She shows concern for Nagini by warning her about Skender's presence, suggesting a sense of shared community or sympathy among the captive snakes (Fantastic Beasts: The Crimes of Grindelwald - The Original Screenplay).

As a non-magical beast, Stheno possessed no inherent magical abilities. However, she was a snake and was therefore able to understand and communicate via Parseltongue. This allowed her to converse with Nagini, who retained her ability to speak to snakes even in human form (Fantastic Beasts: The Crimes of Grindelwald - The Original Screenplay).

Stheno is not known to have had any possessions, being a captive animal at the Circus Arcanus.

• Nagini: Stheno shared a captive bond with Nagini. She acted as a confidante, listening to Nagini's fears and offering her a warning about their cruel ringmaster, Skender. Their interactions highlight Nagini's snake-like nature and her deep unhappiness at the circus.
• Skender: Skender was Stheno's captor and tormentor. He treated Stheno and the other snakes cruelly, using a hook to provoke them for the entertainment of his audience.

The name “Stheno” is taken from Greek mythology. Stheno (from the Ancient Greek: Σθενώ, meaning “forceful” or “strong”) was one of the three Gorgons, monstrous sisters who had snakes for hair. Her sisters were Euryale and the most famous Gorgon, Medusa. The name is a fitting allusion for a character who is a snake.

Stheno is a character created for the Fantastic Beasts film series and does not appear in the original seven Harry Potter novels. Her appearance is in Fantastic Beasts: The Crimes of Grindelwald and is detailed in the film's published screenplay. Her name and connection to Greek mythology deepen the lore surrounding Nagini's origins.