Rosa Dillon

Rosalind "Rosa" Dillon, nicknamed Top by Cisco Ramon, is a meta-human criminal and the romantic partner of Sam Scudder. When she was exposed to the energy of the S.T.A.R. Labs Particle accelerator explosion, she gained the ability to disrupt another person's sense of balance.

Crossing Leonard Snart
In 2013, Rosa and Sam Scudder betrayed their then-partner Leonard Snart by spending the money from their heists shortly after they stole it. Snart was outraged that his co-conspirators would so blatantly flaunt their ill-gotten wealth instead of lying low in the face of pressure from the police, and he confronted the two of them at their hideout in Broome Industries. A physical altercation quickly ensued, and Scudder was overpowered by Snart and knocked backwards on to a mirror while Rosa was subdued by another of Snart's men. It was at this moment that the S.T.A.R. Labs particle accelerator exploded, spreading dark matter and other elements throughout Central City. Though Snart and his accomplice quickly escaped from Broome Industries, Rosa was struck by the energy from the explosion as she tried to help Scudder. Rosa was sent spiraling through the air while Scudder was trapped inside a two-dimensional universe within the mirror, and both became meta-humans as a result of the explosion.

Reuniting with Sam Scudder
Unlike Scudder, Dillon was not so lucky and wound up in Iron Heights Prison for three years after being arrested by the Central City Police Department, where she was held in a specially-built cell with a door fitted with a new type of glass designed to shield the guards from her vertigo-inducing abilities. When Scudder finally managed to free himself from the mirror universe, he tracked Dillon to Iron Heights and broke her out using his powers. Faced with the reality that Leonard Snart was long gone, the duo decided to go on a major crime spree, robbing banks throughout Central City. During one such robbery, Dillon and Scudder found themselves confronted by The Flash and Jesse Quick but Dillon and Scudder were able to escape through another mirror. The two speedsters set off in pursuit; while The Flash went after Mirror Master, Quick confronted Dillon on top of a skyscraper. Remarking on how much she liked her new nickname "Top", Dillon used her power to disorientate Quick, causing Quick to fall off the roof. This distraction allowed Scudder to ambush The Flash and trap him in a mirror.

Team Flash was able to get Barry out of the mirror and used a holographic image of Snart to lure Scudder and Dillon to an abandoned funhouse. While The Flash dealt with Mirror Master, Jessie Quick once more confronted Top who tried to disorient Quick a second time. Quick however was able to shake off the dizzying effect and, after taking Top for a superspeed spinning, knocked her out with a single punch. Once The Flash had dealt with Scudder, Dillon was returned to her cell in Iron Heights while Scudder was locked away in his own cell in the same facility.

Possible Future: 2024
When Barry goes to the future, Mirror Master and Top have taken over the Central City underworld and do as they please as the Flash of the future had retired. They encounter his younger self, who they mistake for the present day version. However, this future has likely been averted considering that in this timeline the Flash did not stop Savitar until 2022, as opposed to 2017 in the current timeline.

Powers

 * Meta-human physiology: After Rosa was struck by the energy of the Particle Accelerator explosion, this altered her DNA and supercharged her cells, augmenting her physiology into allowing her to induce vertigo in people when they look into her eyes.
 * Vertigo inducement: After she was caught in the shockwave of the particle accelerator's explosion, Rosa gained the power to disorient others' sense of balance, triggering a heavy state of vertigo in her victims. Her power works in much the same way as that of Roy Bivolo in that her eyes flash green as well as those of her target, indicating that her power is channeled visually. Rosa was able to create a refraction effect that, when used with the reflection-portals of Sam Scudder, he was able to create portals without a reflective surface.

Behind the scenes

 * In DC Comics, the Top is a legacy name of multiple villains that used disorientation-related gadgets, as well as superhuman speed and telekinesis; the most well-known among them was Roscoe Dillon, a long-time member of the Rogues, who seems to have been the inspiration for Rosa's character in the show.
 * Rosa's powers in the series are very similar to those demonstrated by Count Vertigo in the comics.

Trivia

 * Having heard her nickname from Jesse Quick, Rosa liked it in a similar way to her ex-partner in crime Leonard Snart liking his nickname Captain Cold, also coined by Cisco Ramon.
 * As seen in 2024, Rosa is still with Scudder, but has to constantly remind him that they share the city.