Marda Ro was a female Evereni who lived in 382 BBY as part of the Ro family. At that time, she was on the planet Dalna as part of the Path of the Open Hand cult alongside her cousin, Yana Ro. Marda respected and believed in the cult's leader, the Mother. Ro was quiet, cool, and collected.
Marda Ro met a Pantoran Jedi named Kevmo Zink during the Jedi Order's mission to investigate the missing Rod of Seasons. Due to the Path's beliefs in avoiding the use of the Force, Ro and Zink challenged each other's ideologies, but Ro fell in love with him all the same. When Zink fell victim to the Leveler, Ro blamed the Jedi, not the Mother, for his demise, reasoning to herself that Zink had been indoctrinated into the wrong belief system by the Jedi. She also reasoned to herself that Zink's death was an act from the Force to balance itself. As such, she resolved to bring down the Jedi Order on the belief it would better the galaxy and escaped Dalna with the rest of the Path aboard the Gaze Electric to travel to the holy moon Jedha. Ro was thus dubbed the "Guide of the Path of the Open Hand."
However, the Convocation of the Force on Jedha did not accept the Path's petition and the Herald sparked a riot that engulfed the Holy City in violence and became the Battle of Jedha. Having brought the Path there, Ro was looked down upon for the carnage she had brought them to. However, she met Bokana Koss during the battle, who supported her and who she developed romantic feelings for. Wanting to prove herself after her perceived failure, Ro joined Path member and prospector Radicaz Dobbs and his team as well as Koss on a mission to the fabled Planet X to retrieve more Nameless. While they retrieved many eggs, they were attacked by guardians called the Under-Dweller and the protector and Koss sacrificed himself to stop the latter creature. Blaming his apparent death on abuse of the Force, as Koss had developed Force-sensitivity, and feeling incensed with rage and purpose, Ro appeared before a crowd that the Mother had gathered to witness the hatching of the newly retrieved Nameless eggs. Ro declared that the Path of the Open Hand would become a Path of the Closed Fist to fight back against and defeat the Jedi, incensing them to engage in battle with Jedi that had come to Dalna, leading to a massive battle that became known as the Night of Sorrow.
After the battle, Ro learned that the Mother had been lying to the Path about her supposed visions and had been hypocritically using the Force herself. She thus killed the Mother with the Leveler. Marda parted ways with Yana and set out to carry on the mission to free the Force with a new plan. As she sat on the flight deck of the Gaze Electric, Marda used brikal-shell paint to paint three jagged lines on her head, founding the Nihil. She gathered many remaining members of the Path of the Open Hand who had never known the Closed Fist into her operation, encouraging them to perform raids and take what they wanted. She brought the Leveler with her, taking care of the creature and feeding it Jedi. She also started to search for more of her species in the hopes of starting a family. After finding an Evereni old man only known as "Isren," which meant "old uncle," who taught her much about their people, she eventually located the Evereni siblings Vika and Velya Faer, welcoming them among her number. After a clash between Vika and Alirya, Ro's right hand, left both dead, Ro invited Velya, who had developed romantic feelings for her, to be her new right hand and the two entered a close relationship.
At a very young age, Marda Ro and her cousin Yana were taught the Evereni art of saying or avoiding goodbyes by their mothers. She couldn't remember her life before living with the Path of the Open Hand, although she suspected her cousin did.
On their last night on the planet Genetia, the Ro family was attacked by Genetian townsfolk when Marda and Yana were only children, after the family was blamed for crop failure. During the attack, Marda Ro's sire had fought viciously for the family's escape, whereas the cousins' grandparents were killed along with Yana's sire. The rest of the Ro family managed to escape Genetia after Yana's mother and Marda's mother had killed a family of Theelins and had stolen their ship.
After fleeing Genetia, the Ro family had spent days going hungry and cold after the ship's life support systems began to fail. Eventually, their ship was towed by a Hutt Clan trawler to Nar Shaddaa, where the Hutts attempted to force the family into slavery. The Path of the Open Hand intervened and paid for the Ro family's release.
Marda and Yana's mothers decided to leave their daughters to the Path of the Open Hand. While Marda remembered coming to the planet Dalna as a child feeling lost and scared, she believed their mothers would have wanted the two cousins to stay together. Marda coped with the bloodshed and trauma of their escape from Genetia by assimilating into the Path and learning everything she could in regards to the cult's teachings. For years after their initial arrival on Dalna, Marda and Yana had lived as members of the Path, with Marda growing to love the Path and ultimately coming to supervise the Littles of the Path. Marda's memory of the events that led to her and her cousin joining the Path were, in Yana's eyes, scattered and nonsensical. All Marda would remember as she grew up as a devout member of the Path was the safety, security, and sense of belonging it brought her.
Eventually Marda founded the Nihil pirates. She taught her granddaughter, Shalla Ro to not imprison Jedi behind bars, but with pain instead.
At some point, Marda died, and her story echoed down the following century to her descendant Marchion Ro. As a child, Marchion heard Marda's name "a thousand times". In 229 BBY, Marchion mentally noted he had heard Marda's voice in recent weeks. Afterward, she began to appear to Marchion as a ghost in different forms: when she was young and a member of the Path of the Open Hand, or as an old woman. In 228 BBY, as Marchion carried out investigations of the plague known as the blight, Marda's ghost appeared to him at various points.
Marda Ro was a character created for the 2022 young-adult novel The High Republic: Path of Deceit, written by Tessa Gratton and Justina Ireland for the Star Wars: The High Republic multimedia project. She was first revealed on the cover of Path of Deceit along with her concept art on an episode of The High Republic Show, which premiered on April 13, 2022.