Indeed, Dorian Gray does end up doing much wrong to Miss Vane which induces her to commit suicide. However, her brother, a worldly seaman, does not get the opportunity to fulfill his promise, for he too ends up dead through the machinations of the evil Dorian Gray. Dorian's third mistake occurs at the conclusion of the story when he decides to destroy the painting which after many years has become decayed and horrible to see as a result of Dorian's hedonistic lifestyle and the murder of Basil Hallward. While in the attic where the painting has been stored and kept from prying eyes, Dorian takes the same knife he used to kill Basil Hallward and stabs the painting, thinking that "as (the knife) had killed the painter, so it would kill the painter's work...it would kill the past... It would kill his monstrous soul-life and... he would be at peace" (167).

But when the knife penetrates the painting, "there was a cry......

And a crash... (a cry) so horrible in its agony that the frightened servants woke." When the police arrive, they enter the attic and see "a splendid portrait... In all the wonder of (Dorian's) exquisite youth and beauty," and lying on the floor is "a dead man, in evening dress, with a knife in his heart... withered, wrinkled and loathsome of visage" (167).
Thus, Dorian Gray, believing that the painting harbored his own sins and crimes against humanity, has paid the ultimate price for his vanity and egotism, namely, his own death at his own hands. However, the painting itself never actually changed, for it was all in Dorian's mind. In essence, Dorian Gray became his own worst enemy by wishing to retain his youth in defiance of God and the natural world.

Bibliography

Wilde, Oscar. "The Picture of Dorian Gray." Complete Works of Oscar Wilde. Intro. Vyvyan Holland. New York: HarperCollins, 2002.