Agency in the isekai genre is frequently a privilege of the protagonist, manifesting as a direct correlation between self-will and systemic power. Comparing a YPS-3 authority-user to a YPS-4 physical combatant is fundamentally flawed because their abilities operate on different planes; one manipulates the arcane essence of a world, while the other optimizes the mechanics of a system. The real divergence lies in their DNA Ego scores, which reveal how the genre treats autonomy differently based on narrative role. Kirito’s maximum Ego score reflects a world that bends to his determination, where his ability to bypass system limits through sheer willpower in Aincrad or Alicization proves that his will is the primary engine of the plot. In contrast, Beatrice possesses significant destructive capacity, yet her low Ego score highlights a tragic reality: for the supporting cast, power is often a gilded cage. Her centuries of waiting for "That Person" turned her arcane mastery into a tool of stagnation rather than liberation. The narrative shift occurs not when Beatrice gains more power, but when she accepts the vulnerability of a bond with Subaru. While Kirito uses his bonds to anchor his identity as a protector, Beatrice must use her bond to destroy her identity as a lonely librarian. This reveals that while the protagonist's growth is additive—accumulating skills and allies—the supporting character's growth is subtractive, requiring the shedding of ancestral directives to achieve actual autonomy.