Optimization is the silent enemy of characterization in the isekai genre. Comparing a YPS-3 physical specialist to a YPS-7 hybrid sovereign creates a fundamental category error; the gap between a city-level blast and the ability to rewrite physical laws renders traditional combat metrics useless. Instead, the real friction exists in their opposing philosophies regarding utility. Megumin represents a deliberate rejection of the genre's drive for versatility. By tethering her entire identity to a single, incapacitating spell, she transforms a mechanical limitation into a moral victory. Her "Path of Explosion" is not a strategic choice but an aesthetic manifesto, proving that irrational obsession provides more narrative texture than a perfect build. Rimuru, conversely, embodies the logic of the additive. From consuming the Orc Disaster to the evolution into an Ultimate Slime, every acquisition serves a broader systemic goal. Rimuru does not seek a personal identity through limitation but constructs a corporate-style federation through total capacity. While Megumin finds meaning in what she refuses to learn, Rimuru finds stability in what they can absorb. This reveals a core tension in modern fantasy: the struggle between the romanticism of the specialist and the efficiency of the generalist. One character defines herself by the void she leaves in her skill tree, while the other defines themselves by filling every available slot.