Hermine serves two roles. She is both a kindred spirit to Steppenwolf and source of change for him. When Hermine first appears, it is difficult to determine if she is in fact a real character or one of the possible characters the nephew alludes to when describing the "partly diseased, partly beautiful, and thoughtful fantasies" that comprise the manuscript Steppenwolf left behind. Whether or not she exists in the nephew's world, she is certainly real within Steppenwolf's manuscript, and her effect on him cannot be over emphasized.
Hermine recognizes Steppenwolf for what he is the moment she sees him. She is a courtesan, so she has ample experience "reading" men, as well as noting their needs, both physical and mental. After Steppenwolf leaves the professor's house, he goes to the Black Eagle as a way of delaying his impending suicide. Hermine perceives Steppenwolf's desperation, his desire to kill himself, and his fear of death, which prevents his course of action. Steppenwolf is distraught and irrational about his condition, and Hermine knows this. Rather than engage in a fruitless debate over the frailty of the human spirit, and Steppenwolf's in particular, she assumes an immediate maternal role and orders him to eat and sleep. She states, "You're a baby and you need someone to look after you." This role-playing is exactly what Steppenwolf needs. He will not allow himself to deviate from his plan to commit suicide, so such a postponement can only result from submission to a higher authority — in this case, a mother. Steppenwolf is grateful that he cannot refuse her commands.
Hermine's relationship with Steppenwolf becomes more convoluted every time they are together. On one hand, Hermine is the only individual Steppenwolf has ever encountered who understands his internal division. Hermine knows the treatise, and she accepts the notion that the human soul is fragmented — that it consists of a "thousand selves." She maintains her position of authority over him by acting as both a mother and a teacher. As a mother, she tells him what to do, and she praises or criticizes his efforts. As a teacher, she instructs Steppenwolf in various types of physical sensations and pleasures. She teaches him to dance and to eat, and she arranges for Maria to teach him sexual pleasure. Hermine's behavior strengthens the treatise and its effect on Steppenwolf because she exposes him to some of his other selves. He is uncomfortable with the changes Hermine fosters upon him, but he submits because such changes validate the treatise's premise.
Their relationship is further complicated by Hermine's prediction that they will eventually be lovers, and Steppenwolf will kill her. To say that Steppenwolf is put in an awkward situation would be a grand understatement. From the moment he meets her, Steppenwolf is compelled to accept Hermine and her demands unconditionally because she establishes maternal authority over him. In addition, her knowledge of the treatise, as well as her actions and behavior, serve to authenticate the treatise and the notion of multiple selves. She is a Steppenwolf, and she reveals several of Steppenwolf's other selves; therefore, she is irrefutable. The promise that they will be lovers forces Steppenwolf to look at Hermine from a different perspective, or essentially from the point of view of a different self. In the old relationship, she was the authoritative parent while he was the submissive child. The impending relationship will be based on love, sex, and mutual understanding. In other words, they will be kindred spirits, lovers, friends, and equals.
Hermine is a fundamental component of the Magic Theater, and as such, she is instrumental in Steppenwolf's self-discovery. Steppenwolf describes his initial meeting with Hermine as wondrous: "The miracle had happened. I had found a human being once more and a new interest in life." However, he is still fixated upon death and suicide when he enters the Magic Theater. Hermine presents herself as a female Steppenwolf. She appeals to his lost innocence by dressing as his childhood friend Herman. Her resemblance to Rosa Kreisler associates her with pure love, as well as regret. Her death wish and announcement that Steppenwolf will kill her when she commands him to do so mirror Steppenwolf's own desire for death, as well as his inability to destroy himself. In effect, Hermine is Steppenwolf, but in female form.
It is important to remember that everything in Steppenwolf's manuscript has been filtered through his mind, so it is entirely possible that he simply projected his death wish upon her during their first date. After he "murders" her in the gallery, Steppenwolf admits:
When Hermine had once, so it suddenly occurred to me, spoken about time and eternity, I had been ready forthwith to take her thoughts as a reflection of my own. That the thought, however, of dying by my hand had been her own inspiration and wish and not in the least influenced by me I had taken as a matter of course. But why on that occasion had I not only accepted that horrible and unnatural thought, but even guessed it in advance. Perhaps because it had been my own.
In effect, Hermine's murder is actually a cheap imitation or substitution for his own desire to kill himself. It is only after he kills her in the Magic Theater, that Steppenwolf realizes he has murdered his soul mate, and thereby part of himself.