So why is it that the "big brother didn't lose" Rengoku Kyojuro's popularity is also at an unparalleled level? It's not because Rengoku is the strongest, the most handsome, or has the most breathtaking battle scenes, but because he embodies the ultimate version of Self-as-an-end. He unconditionally and consistently regards himself as an end in itself. This is a fully autonomous state of being, which is almost extinct in modern society. Most Demon Slayer characters, and even most people in reality, harbor self-doubt: Am I worthy of respect? Am I useful enough? Do I deserve to live? But the Flame Pillar doesn't wrestle with these questions. His fundamental assumption is that life is inherently worth existing as an end. I am a person, so I am an end. I don't need to perform well to be worthy; just by existing, I am worthy. This is a form of dignity that requires no external judgment, and it is the purest form of Self-as-an-end. From a power perspective, many strong individuals unconsciously turn their strength into a reason to dominate others or a tool to judge others' worth. Rengoku, however, has none of that. His power is solely used for bearing burdens—taking on danger, responsibility, and even the fears that others need not face. Power isn't used to prove I am above you, but to confirm that I am willing to shoulder a little more. This is a very rare ethical stance on power. In financial terms, Kyojuro never collateralizes his personality for gains, never collateralizes the future for present advantages, and doesn't securitize himself. His balance sheet is extremely simple: assets are ability and willpower, liabilities are zero. Death for him isn't bankruptcy or liquidation but a natural termination. That's why he doesn't panic in the face of death—people without liabilities aren't afraid of liquidation. Since he practices Hegel's freedom and rationality, he also confronts Camus' ultimate judgment head-on. So what is the key difference between the Flame Pillar and the other Pillars? Many Pillars also embody Self-as-an-end, but they are mixed with impurities—some blame themselves, some regret, some carry strong compensatory psychology. Rengoku almost has no internal debt; he doesn't feel he owes the world, doesn't feel the need for redemption, and doesn't think he must prove anything. He simply believes this is the life he chose. This guilt-free integrity is extremely rare. It also makes him feel like the sun—steadily releasing energy without seeking anything in return. He encourages others, affirms their direction, but never demands reciprocation. When a person doesn't need others to prove themselves, they naturally become a source of energy for others. It can be said that Rengoku and Akaza form a perfect mirror image of opposites. Akaza has the ability to embody a purpose but insists on using himself as a tool; Rengoku has the ability to use tools for greater benefits but refuses to do so. This strong autonomous choice also successfully inspired Tanjiro during sacrifice. Regarding views on power, Akaza seeks to prove value, while Rengoku bears responsibility. Regarding attitude toward the self, Akaza believes one must be useful, while Rengoku believes he already has intrinsic value. When facing death, Akaza fears failure; Rengoku accepts the end. Therefore, their confrontation is not fundamentally about combat strength but a pure contrast of "self-toolization" vs. "self-purposeness." Akaza's popularity comes from resonating with pain, while Kyojuro's popularity comes from spiritual aspiration. Viewers see in Rengoku that if one day I become mature and complete enough, I also hope to see myself this way. This is a form of upward projection. Rengoku Kyojuro's strength isn't about how many enemies he can defeat but about never seeing himself as an object that needs to prove his worth. In an era where everyone is chasing performance and efficiency comparisons, this is an almost lost form of subjectivity. The big brother truly didn't lose.