Loyalty in isekai often functions as a mechanism for character stagnation, yet these two figures utilize servitude to achieve opposite psychological ends. A direct YPS comparison fails here because the gap between YPS-3 Authority and YPS-5 Physical is too wide to be meaningful; one manipulates the arcane laws of a library while the other reshapes continents. Instead, the real story lies in their identical Ego scores of 15. For Beatrice, this lack of self-determination is a trauma-induced paralysis, a centuries-long purgatory spent waiting for a ghost. Her arc is defined by the struggle to move from a passive object of destiny to a proactive partner for Subaru. Conversely, Diablo’s low Ego is a voluntary surrender. As a Primordial, his servitude to Rimuru is not a shackle but a curated obsession, a way to channel apocalyptic power into the aesthetics of a butler. While Beatrice’s growth trajectory of 60 reflects a hard-won victory over nihilism, Diablo’s flat growth of 20 proves that for some entities, the peak of existence is simply finding a master worth serving. One views the contract as a rescue, the other views it as a game. This reveals a core tension in the genre: power is either a burden that isolates the soul or a tool that makes servitude a luxury.