Magnus the Red (Demon Prince)

Despite abandoning the Imperium after Leman Russ destroyed his planet, he retained his chastity. He still harbors some regret that he was unable to warn the Emperor of Horus's treachery.

Biography
Born on the planet Prospero, home to space sorcerer-psykers hiding from the Imperium, Magnus was tainted by mysterious chaotic currents, turning his skin red.
He possessed innate psychic abilities and sought to understand the nature of the Warp. However, his careless use of these psychic gifts led to Magnus falling out of favor with his father, the Emperor of Mankind, and most of his brother Primarchs.
After his betrayal, the Changer of Ways elevated Magnus to the rank of Daemon Prince and gifted him the Planet of the Sorcerers, where he plots his plans against the Imperium.

Capabilities
Master of magic and secret disciplines - master of many extrasensory disciplines (telepathy, telekinesis, foresight, etc.).
Reality Manipulation - Can bend or warp the boundaries between real space and the Warp, alter physical laws, and project psychic force on a massive scale.
Extrasensory Vision - Magnus's single eye (the Cyclopean Eye / "Eye of Magnus") allows him to peer deeper into the Warp, perceive psychic phenomena, read minds or discover secrets, and sometimes even foresee events.
Regeneration and Immortality - As a Daemon Primarch, Magnus can heal from severe wounds, is immune or resistant to many forms of damage, is immortal, and cannot be killed by conventional means.

Role in the plot
In the 41st and early 42nd Millennia, Magnus, the Champion of Tzeentch, leads his cursed Legionaries in secret plots and wars against the Imperium of Man.
In M32, Magnus, seeking revenge on the Space Wolves for the burning of Prospero, leads his Thousand Sons in an assault on Fenris, the Space Wolves' homeworld, in what is known as the Battle of the Fang.