The individual known as The Ronin was once a male human who had been a Sith. Following the collapse of the Sith rebellion, he became a wanderer on the fringes of the Outer Rim Territories. He would eventually gain the additional name Grim. This Ronin had initiated the aforementioned rebellion as the Dark Lord of the Sith. He commanded the Sith armies after their separation from the Jedi clans, as they wished to determine their own path and bring an end to the endless conflicts between rival feudal lords and their Jedi knights. The lords created alliances and dispatched their Jedi to fight against the dark lord, his witch, their combined forces, and the Sith demons that the witch brought back from death. However, the dark lord grew disillusioned with the Sith's actions during the rebellion. He then betrayed his followers, effectively ending the rebellion. He then disavowed the Sith, abandoned his former identity, and became the Ronin. With the failure of the rebellion, the former rival lords united to form a renewed Empire that held dominion over a large portion of the galaxy.
Accompanied by his loyal astromech droid, B5-56, the Ronin chose to live in exile in the Outer Rim, never speaking about his previous life. He pledged loyalty to no clan, dedicating himself to hunting down and eliminating other Sith. He collected their kyber crystals to prevent them from being used for malevolent purposes. The disembodied voice of the Witch both guided and tormented him, and he would sometimes respond to it aloud.
Two decades following his rebellion, he encountered a village on the planet Genbara that was under attack by a group of bandits led by Kouru, who styled herself as a Dark Lord of the Sith. Their lightsaber duel concluded with the Ronin killing her, but she was resurrected as a Sith demon.
As the Ronin traveled onward, he encountered the Traveler after hearing them playing a flute. The Traveler then accompanied him to the Osou spaceport.
Before the Empire's reunification, Jedi knights served various feudal lords who were in a constant state of war. The Sith emerged as a dissenting group from the Jedi clans, seeking the freedom to govern themselves and to put an end to the ongoing conflicts that plagued the galaxy. The individual who would become the Ronin had previously held the title of Dark Lord of the Sith. He was the one who initiated and spearheaded the Sith rebellion against the feudal system that dominated the galaxy. Working alongside a Sith witch, the future Ronin led the rebellious faction. The witch had the power to resurrect the dead before they could become one with the Force, transforming them into Sith demons who continued to fight for the Sith cause.
In his role as the dark lord, he developed lightsaber auxiliary technology that enhanced the capabilities of lightsabers. The blueprints for these designs were disseminated among the Sith cells. After the young warrior Kouru constructed her lightsaber, she received the dark lord's blueprints for creating a parasol auxiliary, and her Sith master crafted a fan auxiliary. The dark lord and the Sith witch were in a romantic relationship, and they conceived a daughter, a fact unknown to the dark lord.
During the great muster on Rei'izu, the dark lord gazed into the sacred kyber mirror of Shinsui Temple and witnessed a vision filled with horrors and warfare. This vision caused him to become disenchanted with the rebellion he had started, leading him to turn his lightsaber against the Sith who had followed him. The Ronin's change of heart marked the end of the Sith rebellion. Following the rebellion's conclusion, the Empire was brought back together through alliances between the rival feudal lords, and the Jedi became the most trusted servants of the Emperor. The Sith became increasingly rare in the galaxy, hunted by Jedi Knights, agents of the Empire, and the Ronin himself. Unbeknownst to the Ronin, the witch gave birth to their daughter on Rei'izu.
Two decades after the Sith rebellion, the Ronin traveled through the Outer Rim Territories with his droid companion, B5-56. At one point, a lord fired a blaster at the Ronin. Although he managed to avoid the shot, it struck the left side of his face, leaving his jaw disfigured and scarred. After this incident, the Ronin wore a metal prosthetic that supported his jaw from ear to ear. He also took the lord's blaster and carried it on his own belt. He also began to hear a mysterious voice in his head, urging him towards danger. He dedicated his life to hunting down other Sith, collecting their kyber crystals to prevent them from causing further harm.
Eventually, the pair arrived on the planet Genbara, where the Ronin stopped at a teahouse located just outside a village. He repaired the shopkeeper's power droid in exchange for food and tea. It was then that a gang of bandits led by Kouru, who called herself a Dark Lord of the Sith, attacked the village. Kouru's bandits gathered the village's residents in a central area, but a group of bounty hunters who had been hired to protect the village launched a counter-attack. They began to gain the upper hand when Kouru appeared, killing a Trandoshan guard with her lightsaber parasol.
B5-56 sustained damage from shrapnel caused by the attackers. The Sullustan shopkeep, who had previously worked as a mechanic, offered to repair the astromech. The Ronin entrusted his droid to the shop owner while a pot of tea was brewing and then went to confront Kouru. The former Sith casually walked down the village road towards the bandit leader amidst the chaos until he reached her. Kouru questioned who dared to challenge her, commenting that the man did not appear to be a villager. The errant Sith identified himself as "just a simple wanderer." Kouru removed the parasol auxiliary from her lightsaber and leaped aggressively to strike him. However, the Ronin used telekinesis to freeze the bandit in mid-air, prompting her to boast, "it's been a long time since I killed a Jedi." The Ronin drew his red lightsaber and retorted that he was not a Jedi, which was unfortunate for her, because if he were, she might have had a chance.
The two dueled in the village square before moving to a river. They continued their fight on floating logs down the river to the edge of a waterfall that concealed a temple. The bandits had killed all but one guard, a Gran, when the shopkeep's tea finished brewing. At that moment, B5-56 flew into the air and launched a barrage of missiles that killed every bandit except Kouru.
The Ronin jumped off the log on which he and Kouru had been balancing and set up an ambush in the temple below. Kouru followed his footprints into the temple, where she saw the more elegant of his lightsabers activated. She struck the being holding his saber, cleaving it in half, only to discover that it was a metal statue of a Jedi rather than her opponent. The Ronin then killed Kouru, stabbing her through the chest with the blade of his scabbard auxiliary. After returning to the village, he was initially mistaken for a Jedi knight by the child village chief. He demonstrated that he was not a Jedi by unsheathing one of his red blades and using it to shatter Kouru's lightsaber hilt. Although he initially collected the crystal from within, the voice in the Ronin's head pointed out that the boy had a familiar look on his face. Realizing that the boy was too eager to grow up but lacked the protection to survive, the Ronin gave the crystal to the child, saying it would ward off evil.
As the Ronin traveled to the Osou spaceport, he encountered a being who was playing a flute with limited musical skill. They asked the Ronin to refer to them as the Traveler.
After his identity as a Sith was revealed, he was pursued by the mobilized Genbara army, but he was intercepted by Kouru, narrowly escaping her grasp.
Despite not being in his prime during the decades following his rebellion, the Ronin was a skilled lightsaber duelist and proficient in using the Force. During his duel with Kouru on Genbara, the Ronin believed that his sensitivity to the Force had diminished due to a lack of practice.
The Ronin had long been skilled as a mechanic, with the Force enhancing his natural ability to understand the workings of electrical and mechanical systems, including droids and vehicles. He believed that these talents gave him a better understanding of intricate electronics than other sentient beings. He used his repair skills to earn credits, food, and lodging during his travels. Similarly, his mechanical genius made him skilled at designing the Sith lightsaber auxiliaries and at dismantling starships.
Following the Sith rebellion, the Ronin used a prosthetic jaw support due to a prior blaster injury. Later, he used a respirator after his duel with Hanrai resulted in weakened lungs. The Ronin carried two lightsabers, one with an elegant hilt sheathed in a scabbard made from other lightsaber hilts, and the other a scabbard auxiliary with a cruder appearance. He used the former lightsaber more openly, while the second served as a backup and was used to deceive his opponents. He also carried the blaster that had injured his jaw and kept it in good condition.
The Ronin made his first appearance in "The Duel," a short film and episode of Star Wars: Visions produced by Kamikaze Douga and made available for streaming on Disney+ on September 22, 2021.
In reality, rōnin were wandering, masterless samurai warriors in feudal Japan.