The Master clucked gently, shaking his head. "Ah, but he's had a couple hard regenerations since you knew him. Oh, Jack does have his uses, and the companion the Doctor most recently lost did have the brilliance - or perhaps foolishness - to make sure dear Jack couldn't die. Ever."
He smiled fondly at the memory of the year that the Doctor had erased from the universe. A year of finding new and inventive ways of killing Jack when he got bored. He looked back at Adric, a trace of pity on his face.
"But really, what does an immortal human have to offer the Doctor besides a pretty face and a headache from a paradox he can't fix?" He glanced away a moment, tilting his head. "Well, and willing body to screw if he wants it. Not that Jack would care about who or what he fucked."