Magnus is the oldest child of Pug and Miranda older brother to Caleb. He is a magician, tall, with pale blue eyes and blond hair that almost borders on white. He is one of the most puissant magic users on Midkemia and it has been suggested that he will one day eclipse his parents in the craft, an observation which is agreed upon by the Gods of Midkemia. Magnus is a member of the Conclave of Shadows. He is the only magician besides Miranda who can translocate from place to place without having to have been in the place before. Once, when he journeyed to the Halls of the Dead to plead Lims-Kragma he was able to force a change and take her from the Halls of the Dead to the Pavilion of the Gods. It has been noted that Magnus has a predilection for blowing things up, likely due to inheriting his mother's temper.
Magnus plays a key role in the teaching of Talon of the Silver Hawk, the future Champion of the Masters Court in Roldem, turning him into a valuable Conclave agent.
Magnus is instrumental in the tracking down of rogue Necromancer Leso Varen in Kesh, and is part of the final confrontation with the Conclaves' enemy. He, along with Pug and Miranda, distract the magician so that Bek can run him through from behind. He also travels to the Dasati home world with Pug, Nakor, Murtagh and Bek, disguised as a Lesser. Magnus participates in the final struggle against the TeKarana's Deathpriests on Omadrabar.
Magnus and the rest of the Conclave fight to prevent Dahun entering into Midkemia from the Fifth Circle. During the attack on Sourcerers Isle by the Demon Legion, Magnus' mother Miranda, and his brother Caleb, are slain. Magnus and Pug prevent what they believe is Dahun entering Midkemia, but is actually Belasco trapped in the body of the Demon Prince.
Magnus unlocks the secret of the Sven-ga'ri on the Island of the Serpent men, only to trigger the trap set by the Dread, which placed the beautiful beings on Midkemia as markers, their profound emotional contact defending them against the Valheru. Magnus plays a pivotal role in the final confrontation with the Dreadking in E'bar, by channeling energy from various magicians and priests so that Pug could plug the Void, thus preventing the collapse of time. Magnus is slain by the resulting magical backlash, but is resurrected when Pug intercedes with the gods on his behalf.