The incarnation of Omega present during the time of the Triumvirate on ancient Gallifrey, was “…a definite drift from the regenerative norm” and possibly a genetic memory from the Dark Times (Ben Aaronovitch, Remembrance of the Daleks, Target Books, 1990).
Harry looks down at him, at the way the sun streams over his face and shoulders, at the way the gag stretches his mouth, lips pink and chapped. He’s lithe and pretty, smudged all over with dirt. They had found him tied up below deck, mostly unconscious, next to a barrel full of gold. He’s clearly a prisoner, but there’s something familiar about him, something that niggles at Harry’s brain. Something he can’t quite put his finger on.
“Put him in my cabin,” Harry decides, turning back to deal with the rest of the loot. The boys screams out jumbled curse words at Harry’s back, muffled by the gag, and Harry can’t understand any of it.