As the Eye of the Nihil during the High Republic Era, Shalla Ro commanded the Nihil pirate band. This female Evereni belonged to the Ro family. Being the founder's daughter, she also bore a son, Asgar Ro, with another Evereni male. Marchion was Asgar's son, making him Shalla's grandson, and would later become a key figure in the Nihil. Shalla advocated for a more measured approach to the Nihil's expansion, employing strategy and caution in her leadership. She viewed Marchion as the embodiment of Evereni resilience, destined to challenge the Galactic Republic and the Jedi Order and avenge the Ro family. This cautious philosophy clashed with Asgar's desire for rapid growth. Their disagreements culminated in 252 BBY when Asgar killed Shalla, seizing the title of Eye for himself.
During the High Republic Era, Shalla Ro, an Evereni woman, was the daughter of the Evereni woman who established the Nihil pirate organization. Shalla's grandmother, Marda Ro, created a recording for her descendants, including Shalla, detailing a portion of her life. Kassav Milliko, a Tempest Runner and Nihil member, mentioned that the Nihil and Shalla shared a "history." Shalla had a son, Asgar, with a male Evereni. Asgar, in turn, had a son named Marchion Ro. Shalla, following the teachings of her grandmother, instructed Marchion that Jedi could not be held by physical restraints, but through the infliction of pain. Shalla repeatedly asked Mari San Tekka, a Force-sensitive hyperspace prospector with the ability to locate unconventional hyperspace routes known as "Paths," who was held captive by the Ro family, to explain her abilities, but San Tekka could not clearly articulate it. Because she wanted to be careful in the expansion of the Nihil, Ro was hesitant to overuse San Tekka's abilities. During Marchion's youth, Shalla and Asgar would tell him stories about Planet X, the homeworld of the Nameless creatures.
In 252 BBY, Shalla held the title of Eye of the Nihil, leading the Nihil. In that year, she and Asgar debated the Nihil's direction aboard their flagship, the Gaze Electric. Shalla likened the Evereni survivors to blades, with Marchion representing the sharpest point. She approved of Marchion's connection with San Tekka, believing it would be advantageous in the future. Shalla further expressed that Marchion would ultimately confront the Galactic Republic and Jedi Order, and Asgar should continue to "sharpen" him for the coming conflict.
Asgar countered that the Nihil needed more immediate action, given San Tekka's advanced age of over a century. He argued that Marda would not have tolerated such inactivity. Shalla retorted that she had witnessed the Jedi's power firsthand and advocated for continued patience. She suggested Asgar emulate his father and grandfather by venturing into the galaxy and accumulating kills, a proposal Asgar accepted. However, believing himself a superior leader, Asgar pushed Shalla over a railing, resulting in her death upon impact with the floor.
Following Shalla's demise, Asgar left the Gaze Electric aboard a smaller starship. Nihil Tempest Runner Pan Eyta, mistaking him for Shalla Ro, remarked that Shalla was coming to incite the Nihil to make money for herself. Asgar landed and exited the vessel, prompting Kassav to inquire about Shalla's whereabouts. Asgar announced Shalla's death and declared a new direction for the Nihil. Kassav argued that Shalla had a history with the Nihil and was an effective leader, and that, with her gone, it would be easier to simply kill Asgar. Asgar proposed a contest where Marchion would fight against any Nihil ships, and if he won, the Tempest Runners would listen to Asgar. Marchion, utilizing the Paths provided by San Tekka, emerged victorious and assumed the title of Eye of the Nihil. In contrast to Shalla's cautious approach, he oversaw a period of significant expansion for the organization.
After his father's death in 242 BBY, Marchion became the Eye of the Nihil, engaging in extensive conflict with the Jedi Order and the Republic, just as Shalla had foreseen. San Tekka would sometimes confuse Marchion for Asgar or Shalla. In 232 BBY, Marchion invoked Shalla's teachings on Jedi captivity during the raid on Elphrona, when the Nihil captured Jedi Master Loden Greatstorm. Between 231 BBY and 230 BBY, Marchion breached the Veil, which was a barrier preventing ships from landing on Planet X, by first sending in Nihil ships, thus causing the Veil to focus on destroying them. Marchion then used the Cloudship Ikoru to breach the Veil, mirroring the stories Shalla had recounted to him.
Shalla Ro stood at 1.65 meters (5 ft 5 in) tall, with slate-gray skin, black eyes, and black hair streaked with red. She was a strategic thinker who favored stealthy growth for the Nihil. She possessed strong leadership skills, adept at making contact and issuing commands. Kassav described her as a resilient survivor with valuable ideas, but also as "mean as hell."
Shalla's attire included a red dress, a necklace that was a Ro family heirloom, and turquoise earrings.
Shalla Ro was initially mentioned, without being named, in Charles Soule's 2021 novel, The High Republic: Light of the Jedi, part of the Star Wars: The High Republic multimedia project's Phase I. Her first appearance and identification as "Shalla" occurred in a flashback in the first issue of the 2022 comic miniseries Star Wars: The High Republic: Eye of the Storm, which was written by Soule, illustrated by Guillermo Sanna, and published by Marvel Comics on January 12, 2022. The 2023 reference book Star Wars: The High Republic Character Encyclopedia later confirmed her surname as "Ro."