Professor Marcus Scarman, brother to Laurence, was an English archaeologist and a Fellow of All Souls College, Oxford. He lived in his priory in the same village with his brother, until he was killed by Sutekh, who reanimated his body as a heartless undead entity who declared himself the Servant of Sutekh.
Determined to "make a name for himself" by discovering "lost Egyptian tombs and treasures", (AUDIO: Memories of Tomorrow Marcus Scarman discovered the Black Pyramid, the prison of the Osirian Sutekh. Sutekh killed him, but animated his corpse and used it as a vessel of his power. The undead Scarman returned home via a time-space tunnel contained in an Egyptian sarcophagus.
In the full regalia of a "Servant of Sutekh", he killed Ibrahim Namin, a worshipper of Sutekh, and with a small number of Osiran service robots at his command set about doing Sutekh's will. He killed his brother Laurence, witnessed the destruction of the Osiran war missile, and travelled to the Pyramid of Mars with a possessed Fourth Doctor and Sarah Jane Smith to release Sutekh from the Eye of Horus. Despite Sutekh being freed, the Doctor defeated him, after which he relinquished his hold on Scarman's body, allowing him to die. Scarman appeared to regain his humanity, saying "I'm free! Free at last...", in the moments before he collapsed and turned to dust. (TV: Pyramids of Mars)
His priory burned down and the site would become that of UNIT HQ. (TV: Pyramids of Mars) Scarman's remains were never found and he was believed to have been among those who perished in the fire. A newspaper report speculated that, by an unfortunate coincidence, he had returned home from Cairo on the night of the fire. (PROSE: Doctor Who and the Pyramids of Mars) Rumours claimed that the amateur egyptologist had been killed by "the curse of King Tut". (AUDIO: Memories of Tomorrow)
The Eleventh Doctor later mentioned Marcus Scarman when talking about great archaeologists. (PROSE: The Glamour Chase) When introducing himself to Lord Woolcroft, he also claimed to be from the "Scarman institute". (AUDIO: The Hounds of Artemis)