Morbius is the main antagonist of the Doctor Who story "The Brain of Morbius". This was his only on screen appearance although he has appeared in other media.
Morbius was a Time Lord of the first rank who rose to a senior position in the High Council. He tried to convince the Time Lords to conquer other races but was rejected by them. He instead formed an army of his own, promising them immortality via the Elixir of Life, which was guarded by the Sisterhood of Karn. The Time Lords formed their own army and Morbius was defeated on Karn, being sentenced to execution by disintegration. Although sentence was carried out, unknown to anyone at the time, Morbius' brain was removed by one of his followers, Mehendri Solon, prior to the execution.
Solon kept Morbius' brain alive while constructing a body to house it, using body parts from victims of spaceship crashes. Morbius was able to hear and speak but otherwise had no sight or feeling, believing himself worse than a vegetable. However, Solon eventually needed only a head to complete the body. When the Fourth Doctor arrived on the planet, Solon saw him as the perfect donor. However, when he learned the Doctor was a Time Lord, Morbius feared he was there to capture him and take him back to Gallifrey. He convinced Solon to give him life by placing the brain inside a transparent case and attaching that to the body.
The initial attempt caused Morbius' brain to short-circuit, resulting in him attacking Solon and killing both his servant Condo and one of the Sisterhood. The Doctor and Solon captured him but Solon double-crossed the Doctor and repaired the damage, giving Morbius life again. Having failed to kill Morbius by gassing the laboratory, the Doctor challenged him to a mind-bending contest. The effort left both of them badly injured and resulted in the brain short-circuiting again. Morbius was pursued by the Sisterhood of Karn and driven off a cliff to his death.
The novel Warmongers acted as a joint prequel/sequel involving the Fifth Doctor becoming involved in Morbius' initial campaign. The Time Lords appointed him to lead an army of other races which defeated Morbius. Aware of future history, the Doctor allowed Solon to remove Morbius' brain prior to his execution.
The audio play The Vengeance of Morbius saw Morbius revived by one of his followers using a fragment of his brain and genetic material from the Time Lord Straxus. Morbius conquered Gallifrey, enslaved the Time Lords and spent a decade conducting a further campaign before finally being confronted by the Eighth Doctor, who freed the Time Lords. The Doctor and Morbius both fell from a balcony during a struggle. The Time Lords then reversed time so Morbius was never revived.
- Morbius is the first Time Lord antagonist encountered by the Fourth Doctor.