"Do you feel that your body is in exceptional health, that even if you were slashed with a knife, the wound would disappear quickly, leaving not a single mark after a few days, without even a scar?"
He asked Yu.
"How... how do you know that?"
Yu swallowed hard, panic beginning to show in her demeanor as she asked.
"Heh."
The old clan leader chuckled again.
"Why wouldn't I know? The evil influences are eroding you, using your very own lifespan to heal you!
What's called healing is using your own lifespan to mend your wounds. Naturally, injuries that could recover slowly are being rapidly repaired by sacrificing your lifespan!
Moreover, you must have felt it too, haven't you? Since you made a deal with the evil influences, you don't need to sleep or rest, as long as you eat the flesh of the Demon Clan every day.