Complex sentence: James releases Dorian, but then is approached by a woman from the opium den, who reproaches his not having killed Dorian, and tells him that Dorian has not aged in eighteen years; too late, James runs after Dorian, who has gone.
Split into simpler sentences: James releases Dorian but then is approached by a woman from the opium den, who reproaches his not having killed Dorian; she tells Vane Dorian has not aged in eighteen years. Too late, James runs after Dorian, who has gone.