Now a member of the Demon Slayer Corps, Tanjiro travels with Nezuko to a town to the northwest where girls have been disappearing night after night. His first assignment is to track down the Demon abducting the girls and eliminate it.
Tropes associated with First Mission Arc:
- Arc Villain: The Swamp Demon, a demon who hunts for young women and has the honor of being the first target of Tanjiro's first assignment.
- Chekhov's Gunman: Muzan Kibutsuji.
- Hypno Pendulum: Urokodaki uses this to influence Nezuko into protecting humans.
- It's All My Fault: Kazumi blames himself for his fiancee disappearing. Her parents also agree with him.
- The Mob Boss Is Scarier: The Swamp Demon would rather face sunlight than reveal anything about Muzan.
- The Reveal: Muzan Kibutsuji killed Tanjiro's family and turned Nezuko into a demon.
- Sharing a Body: The Swamp Demon is composed of three individual Demons.
- Straw Misogynist: The Swamp Demon.
- You Are Too Late: When Tanjiro insists that the Swamp Demon return the girls he kidnapped, it simply points to its belly, meaning they are long gone.
- You Should Have Died Instead: Kazumi's fiancee's parents towards him.
