Anubekh

"Anubekh" was the name used by the Doctor's companions to refer to a copy of Sutekh's mind, described as a "splinter of himself" by the original. Like Marcus Scarman before him, Anubekh thought of himself as Sutekh, but was aware that he was also merely an extension of Sutekh, a servant of his will. Anubekh possessed Sutekh's Anubis and worked to free Sutekh from the time corridor in which he had been trapped.

Origins
Anubekh described himself as the "first" of Sutekh's splinters when reunited with his original. Inside the mindscape where he overpowered Anubis's mind, Anubekh explained that the original Sutekh had left this splinter of his consciousness buried within Anubis as a "parting gift," to be activated after Anubis recovered the Hand of Sutekh. (COMIC: Old Girl)

Becoming active
This came to be when Anubis began to train the human Dorothy Bell aboard the Shining Horizon, following Bell merging with the Hand of Sutekh, (COMIC: Old Girl) a quantum harvester. (COMIC: The Fountains of Forever) The splinter of Sutekh kept many months gnawing at his son's soul like a virus, occasionally causing him moodwings and blackouts, before fully taking him over. (COMIC: Old Girl)