If the trope continues, Elan has decided to play the, "There is still good in you.", gambit.
However, I predict that Tarquin has foreseen this, and is counting on it. After all, if Elan's gambit were to work, not only does Tarquin get to rule the world, and leave behind a fearsome reputation, but he gets to leave behind the story of his redemption as well. He can spend most of his life as a child slaughtering jerk who enjoyed untrammeled power, yet die a beloved hero.