Siobhan Smythe

Siobhan Smythe is the former second assistant of Cat Grant at CatCo Worldwide Media. After Kara outed her plan to offer her information on Supergirl to the Daily Planet, she was fired by Cat. Soon afterward, she discovered that a family curse gave her the power to sonic scream, and began calling herself Silver Banshee.

CatCo Worldwide Media
Siobhan Smythe was hired to be Cat Grant's new assistant alongside Kara Danvers. Kara was annoyed by being unable to pronounce her name correctly. Cat designated Kara as "Assistant #2" to her confusion. Siobhan promptly one-upped Kara's coffee while Winn looked on uncomfortably. Cat told Siobhan to get James Olsen and Lucy Lane into her office and told Kara to cover the phone, which she then broke. Siobhan later tried to flatter James but was brushed off. Siobhan saw them talking and walked away smirking.

She continued to antagonize Kara by sending her messages asking what's between her and James. Kara asked what she meant and she boldly sent another asking whether they were dating or friends with benefits, which Kara denied, while Winn Schott observed. Siobhan continued sending messages and upset her when she apparently accused her of being "obsessed" with James. Cat arrived and told her to keep it down. When Kara was called away, she reminded Siobhan about Cat's lunch, but Siobhan recited it perfectly and mocked her for not doing her job, winked at Winn and smirked at his uncomfortable reaction. She later tried to listen on James and Lucy's private conversation. Later Siobhan smugly told Kara she did all her work for her. Kara bluntly said she didn't like her, but she retorted she wasn't there to make friends, but to be the next Cat Grant, detailing her massive ambitions, and Kara said they'd see who gets to stay.

Winn Schott
Siobhan continued to put down Winn but she was interrupted by Cat asking everyone in for a conference call. Siobhan showed a package that Cat should see personally, but Cat wants it open for all to see, so James takes the package and opens it to find a letter and flash drive. An unimpressed Cat tells Siobhan to have the drive microwaved. Cat tells Siobhan to call her investment broker, but she stammers for a moment before Kara took the assignment. Winn offers to help Siobhan make copies, but she is upset over finding that her father was listed as a member of a cheating website thanks to Indigo and leaves Winn to make the copies. Later Winn told Siobhan about his family and how he has felt just like her. Siobhan then kisses him but warns Winn not to say anything.

Fired
She continued her secret relationship with Winn until Kara caught them together in a supply closet. When Supergirl has her inhibitions destroyed by Red Kryptonite, Siobhan caught her on tape letting a Khund get away. When Cat refused to run the scoop, she plans to send it to her old employer, the Daily Planet. She planned to use the scoop as her route to returning to Metropolis as a reporter. However, Kara finds the tape, and lured her away from her desk so she can print the email. When Cat found out about Siobhan's treachery, she fired Siobhan on the spot, and persuaded Perry White not to rehire her either.

Frustrated at her apparent blackballing from National City's media industry, Siobhan plots revenge on Kara. She slips into CatCo Plaza after hours and sends a nasty email to Cat on Kara's account. The next night, Cat calls her in. She believes that Kara has been fired and that she is about to get her old job back. However, Cat had Winn analyze the email, and found that the typing pattern was an exact match to Siobhan's pattern. Cat brusquely ordered Siobhan out, and warned her that she would be arrested if she ever set foot at CatCo again. That night, a drunken Siobhan lays into Winn for turning on her, but Winn tells her that resorting to criminal and manipulative behavior will get her nowhere. Suddenly, one of Siobhan's spike heels breaks, sending her screaming over the balcony. To her surprise, the sound waves from her screams break her fall just as she is about to smash into the pavement--blowing a giant hole in the concrete in the process.

Silver Banshee
Winn took her to doctors at the D.E.O., who found that she wasn't an alien. While begging Winn for help, she started hearing a piercing scream inside her head, and also saw visions of a banshee. Later, she implied that she had been dealing with these visions for some time; she said that she had believed for "all my life" that she had been cursed.

Later in the week, she was walking along the streets of National City when the visions and screams returned. Out of nowhere, she stormed into CatCo Plaza and screamed at Kara, sending her flying out of a window, but Kara was rescued by the Flash.

Later, a seemingly distraught Siobhan consulted her Aunt Sinead for help. She learned that years ago in Ireland, one of their ancestors stole something from a banshee. In retaliation, the banshee placed a curse on all of the women in the Smythe family. Whenever a female Smythe is wronged, she is possessed by the spirit of a banshee. Once her powers grow to their full potential, she will be able to send her scream anywhere in the world. However, unless she kills the object of her rage, her scream will destroy her soul. This made Siobhan decide to kill Kara. However, believing that Supergirl had rescued her, she believed she would need to get past Supergirl to get a shot at Kara.

Siobhan proved a quick study with her powers once she fully embraced them. Remembering that Livewire was incarcerated at the D.E.O. and wanted to kill Cat and Supergirl, she sonic screamed from a distance and shattered Livewire's cage. She then lured Livewire to an abandoned warehouse and offered to team up. Livewire readily agreed, but suggested that Siobhan get a new costume and a makeover. Siobhan painted her face white with heavy black eyeliner and put on a gray/silver wig--taking on an appearance similar to the banshee she saw in her visions. At Livewire's suggestion, she began calling herself Silver Banshee.

When Supergirl and The Flash tracked Livewire and Silver Banshee to the warehouse, Supergirl was about to douse Livewire with water when Silver Banshee screamed with enough force to make Supergirl's ears bleed. Livewire and Silver Banshee then stormed CatCo Plaza, with Silver Banshee arriving on Cat's private elevator. Winn tried one last time to talk some sense into Siobhan, but Siobhan tempestuously screamed him to the ground. They then kidnapped Cat and chained her to a bench at National City Park.

As Livewire was about to kill Cat, Supergirl and the Flash rushed in. Silver Banshee tried to scream at them, but it had no effect; the two heroes had enhanced earplugs that the Flash had used on the Pied Piper, an old foe of his who used sound as a weapon. Livewire tried to crash a helicopter, but Kara flew in front of the blast to prevent a potential disaster. As Livewire and Silver Banshee were about to go in on an incapacitated Supergirl, several bystanders rushed in to protect her. Livewire was about to electrocute them all when a fire engine doused her with water. Lightning uncontrollably arcing off Livewire hit Siobhan and incapacitated her. She was then arrested by the National City Police, who with Barry's help, could now contain metahumans.

Powers and Abilities

 * Banshee Curse: Siobhan's powers come from the curse that runs in her family.
 * Sonic scream: Because of the banshee curse that effects her, Siobhan is able to emit high-amplitude screams. The sound waves from her screams are powerful enough to shatter glass and thick concrete, and also break her falls. They are also strong enough to affect two full-sized adults at once, by knocking them off their feet, disorienting them, or even killing them.  Kryptonians are not immune to these screams, either because Siobhan's powers come from a curse (Kryptonians are not protected from the effects of magic), as a side effect of their enhanced hearing, or possibly both. She can also direct her screams over large distances and even send them at specific targets, as seen when she deafened Supergirl without affecting both Livewire and the Flash. As her powers grow she will be able to send her scream anywhere in the world by focusing on her target.
 * Superhuman strength: The banshee spirit that took over Siobhan gave her enhanced physical strength. When the spirit first took her over, she single-handedly threw off Winn without breaking a stride. Later, after fully embracing her powers, she was able to land a hard punch on Supergirl that sent the latter flying several feet.

Season 1

 * "Worlds Finest"
 * "Worlds Finest"
 * "Worlds Finest"
 * "Worlds Finest"
 * "Worlds Finest"

Trivia

 * The Banshee curse apparently makes women in her family 'unlikable', and is probably the reason no one but Winn seemed to like her.