Although his adventures in the novel are incidental, his personality is omnipresent in two-thirds of the book. Vautrin is presented at first as a strongly built, middle-class man, sensual, jovial, likable, who indulges in silly jokes and pranks. And if the delineation stopped there, he would be no more than a younger Poiret. But the character is built on the quality of strength capable of breaking all obstacles. With this attribute, Vautrin becomes the symbol of a fighter, rebelling against a society which has created and degraded him. But physical power means for Balzac mental power as well, and he endows Vautrin with the latter, thus creating a character of incomparable magnitude, capable of dominating everyone.
Of this power, Balzac gives us an inkling in the first section: Vautrin's "eyes, like those of a pitiless judge, seemed to go to the very bottom of all questions, to read all natures, all feelings and thoughts." As the novel progresses, this power increases, to become supernatural and diabolical: "The escaped convict cast a glance at Eugène, a cold and fascinating glance. Men gifted with this magnetic power can quell furious lunatics in a madhouse by such a glance, it is said."
With his physical and mental strengths, Vautrin will assume the role of the diabolical tempter. A keen psychologist, he has soon discovered the latent ambitions in Rastignac, whom he tries to convert to his side by his powerful comments on society, to make of Eugène an instrument of revenge.
But to Vautrin, Rastignac is more than a mere instrument; he becomes a sort of alter ego. Vautrin feels a genuine interest in, and love for, the young man, in whom he can see the attributes he lacks: an aristocratic charm and elegance, allied with a spontaneous naïveté. Thus Vautrin will undertake to mold Eugène to his own image, to perform a sort of spiritual creation.
In Vautrin's character, we find much of Balzac and of his preoccupations. We have noted already the physical resemblance between Vautrin and Balzac; we have seen that Vautrin expounds many Balzacian ideas, that he unconsciously seems to be part of Balzac's dreams of the triumph of pure creation.
This is the reason why Vautrin leaves us with mixed feelings. Although he is presented as a villain, as a cynical and vicious person, as a diabolical tempter, we cannot help but feel toward him the unexplainable feeling of mixed admiration and envy one has for superhuman powers.