# Demon Slayer: Kimetsu no Yaiba, Vol. 21
## The Final Battle at Infinity Castle
- Tanjiro and the Pillars' Desperation
- Tanjiro's Resolve to Save Nezuko
- The Pillars' Sacrifices and Determination
- Muzan's Overwhelming Power
- The Truth About Infinity Castle
- Infinity Castle’s Ever-Changing Structure
- Traps and Illusions Within the Castle
- The Psychological Toll on Demon Slayers
- Key Battles Against Upper Moons
- Tanjiro vs. Upper Moon Daki and Gyutaro
- Flashbacks of Their Past Lives
- Tanjiro’s Use of Hinokami Kagura
- Giyu Tomioka vs. Upper Moon One Kokushibo
- Giyu’s Mastery of Water Breathing
- Kokushibo’s Regenerative Abilities
- Sanemi Shinazugawa vs. Upper Moon Two Doma
- Sanemi’s Anguish and Hatred Toward Demons
- Doma’s Sadistic Nature and Strength
## Emotional Depth and Character Development
- Nezuko Kamado’s Humanity
- Her Struggle to Retain Human Emotions
- Tanjiro’s Unwavering Faith in Nezuko
- Zenitsu Agatsuma’s Growth
- Overcoming Self-Doubt and Fear
- Unlocking New Levels of Thunder Breathing
- Inosuke Hashibira’s Bravery
- His Feral Instincts as an Asset
- Deepening Bonds with Fellow Slayers
## Themes of Sacrifice and Hope
- The Pillars’ Sacrificial Spirit
- Kyojuro Rengoku’s Legacy Inspiring Others
- Each Pillar’s Unique Motivations for Fighting
- Muzan Kibutsuji’s Vulnerability
- Discovery of Sunlight as His Weakness
- Internal Conflict and Paranoia
- The Power of Unity Among Demon Slayers
- Collaboration Between Hashira and Lower-Rank Members
- Shared Goal to Eradicate Muzan Once and For All
## Climactic Moments Leading to Resolution
- Tanjiro’s Transformation
- Awakening of Marked Potential
- Combining Techniques from Multiple Breathing Styles
- Allies’ Support in Critical Moments
- Villagers and Non-Combatants Playing Crucial Roles
- Unexpected Reinforcements Arriving
- Countdown to Dawn
- Racing Against Time Before Sunrise
- Final Confrontation Between Good and Evil