Complex sentence: Charles Rabou, who finished the novel The Deputy of Arcis after Balzac's death, included Vautrin in this story, however, his Vautrin loses most of his former genius.
Split into simpler sentences: Charles Rabou, who finished the novel "The Deputy of Arcis" after Balzac's death, included Vautrin in this story. However, his Vautrin loses most of his former genius.