rung

At the end of Lost Light, it is revealed that Rung is actually Primus, a member of the Guiding Hand and a figure connected to the origins of Cybertronians. His memories of his former identity and history were lost due to the events involving Adaptus and Luna 1. This identity gives new meaning to Rung's journey. For millions of years, he lived as a psychologist without fully understanding who he truly was. He helped others cope with trauma and loss, while he himself lived with incomplete memories.

When Rung joined the crew of the Lost Light, he continued his role as a psychiatrist. He listened to the problems of Red Alert, Whirl, Fortress Maximus, and many other robots. He also kept patient information confidential, even when others urged him to reveal something. But the journey also brought him danger and loss. When Froid reappeared in his life, they briefly worked together in a critical situation. Froid was ultimately killed by Sunder, while Rung chose to stay behind to help Skids, who was suffering from severe psychological damage. Later, Rung also encountered Chief Justice Tyrest, who knew of his hidden abilities. Tyrest tried to involve him in a plan, but Rung refused. When Skids sacrificed a chance to escape to save him, Rung had to face the loss of another friend.

Rung and Froid were once close friends. Rung even once confided in Froid about his personal secrets. However, they soon fell out over differing views on psychological treatment, particularly the use of procedures to alter a person's personality. Rung was more wary of abuse of power, while Froid was willing to support actions Rung considered unethical. Their rivalry worsened when Froid appropriated Rung's personality type classification system and claimed it as his own. For Rung, this was more than just a copyright issue or a career dispute. The betrayal came from someone he once trusted, further damaging his professional reputation. When they reunited, the relationship was far from the old friendship. Froid attempted to use Rung's secret past to pressure him into giving her access to patient records. Rung refused. He maintained his professional boundaries, even when confronted by a former friend who knew the most vulnerable parts of his past.

During the war, Rung served aboard the ship Fateful Archetype. It was there that he became too intimate with a patient. As a result, the ship's tribunal stripped him of his right to practice medicine. However, the ship later suffered a shipwreck, leaving Rung the sole survivor. Because everyone who knew about the tribunal's decision had died, no one knew the story. The only person he ever told was Froid, a colleague with whom he was still close at the time. Their closeness eventually turned into a professional rivalry. They clashed over the use of personality-altering procedures, and Froid later adopted the personality classification system Rung had developed. Their past became one of Rung's most personal sources of conflict.

During the Great War, Rung became one of the Autobots' most trusted psychological specialists. He treated many robots, including those experiencing trauma and emotional difficulties caused by the war. His work wasn't always safe. In the Last Stand of the Wreckers story, for example, he performed a psychological evaluation on Impactor ahead of his trial. Impactor reacted by threatening and attacking Rung, leading Rung to question whether the Autobot leadership was partly responsible for Impactor's actions.

Rung hails from the Pious Pools and has been a renowned psychology specialist since the early Silver Age, during the reign of Nova Prime. He possessed the unique ability to generate photonic crystals, once used in the development of Spark energy storage technology. However, when the Matrix was stolen, his memory of this ability was erased to prevent its exploitation. As the Functionist government rose to power, Rung faced a rather ironic dilemma. No one knew what his alt-mode function was, including himself. Functionist society considered alt-mode functions to determine one's role in society. Rung was ultimately categorized as an ornament, as if his existence had no practical purpose. During the Great War, Rung became one of the Autobots' most trusted psychological specialists. He treated many robots, including those experiencing trauma and emotional difficulties due to the war. His work wasn't always safe. In the Last Stand of the Wreckers story, for example, he performed a psychological evaluation on Impactor ahead of his trial. Impactor reacted by threatening and attacking Rung, leading Rung to question whether the Autobot leadership was partly responsible for Impactor's actions.