Like Legion founder Cosmic Boy, Dyrk is Braalian and was born with the power to manipulate magnetic fields. Even as a child, his powers were very strong, enabling him to move tons of mass.

He participated in the open tryouts held by the Legion (Legionnaires #43) to fill in the roster while half the team was stranded in the twentieth century. Along with Tasmia Mallor of Talok VIII and Princess Jeka Wynzorr of Orando, Dyrk was granted membership in the Legion on the strength of his performance in the tryouts, and he took the codename Magno.

However, his active membership was short-lived. On the rookies' first mission to investigate a cave-in on the mining asteroid Yuen (Legionnaires #44), Magno unwittingly discovered the empty tomb in which the sorceror Mordru had been sealed. Within weeks the Legion battled Mordru directly, ultimately defeating him with the help of several other heroes, but in the process, Dyrk lost his powers of magnetism.

He returned to Braal to consult a string of specialists with no results. Eventually, Live Wire persuaded Dyrk to join the Legion for the dedication of the new Outpost Allon, and Dyrk decided to stay on as support staff, becoming Chief of Operations of the Outpost. In this capacity he assisted the Legion for several years, handling administration, coordination, and monitor duty. He also formed a relationship with XS, and aided Brainiac 5 in defeating Tharok after the Fatal Five briefly took control of the Outpost (Legion of Super-Heroes #124).

During the invasion of Earth by the Blight, Dyrk was not among the Blighted; instead he, like Sensor, Invisible Kid, and Live Wire, was captured using chokeweed, and assumed dead until the end of the Legion of the Damned arc. Following the rift crisis, the loss of Outpost Allen and seven Legionnaires, and the disbanding of the Legion by the United Planets, Dyrk chose to join the Science Police, following the example of his older brother Omar. Upon completing his training he was transferred to his home planet of Braal, and became incolved in the Legion Subterfuge Squad's ploy to steal a faster-than-light "footstep" ship when he arrested Cosmic Boy for vigilantism (Legion Worlds #3). Upon learning of Rokk's true intentions and the secret re-forming of the Legion, Dyrk agreed to cover for his former teammates and allowed the Science Police to assume Cosmic Boy was dead, on the condition that Rokk contact him and explain everything as soon as possible.

That apparently never came to pass, as Dyrk did not appear again in the post-Zero Hour Legion series, and was erased from continuity in the subsequent reboot.