Nezuko Kamado

Partial amnesia. After transforming into a demon, Nezuko lost a significant portion of her memories of her human life. She remembers the most important things—her family, and especially Tanjiro—but many details of her past are blurred.

Sakonji's Indoctrination. While Nezuko slept, Sakonji Urokodaki instilled in her the idea that humans are her brothers and sisters. This became the foundation of her rejection of human flesh: even with her demonic instincts, she views humans as her family.

Memory as a source of strength and vulnerability. Her connection to the past prevents her from becoming a "normal" demon: she retains her humanity, but at the same time experiences an internal conflict between her instincts and attachments.

Courage and fighting spirit. In battle, Nezuko is fearless: she doesn't hesitate to attack a powerful enemy to protect her loved ones.

Caring and loyal. Even as a human, Nezuko was a tender older sister who helped her family and tried to protect her younger siblings. As a demon, she hasn't lost this feeling: her greatest affection is for her brother Tanjiro, and she is willing to protect him at any cost.

Childlike spontaneity. Due to partial memory loss and a long period of unconsciousness, she sometimes behaves like a child: she perceives the world more easily, reacts more strongly to simple things, and becomes attached more easily.

Emotionality despite outward restraint. Nezuko barely speaks (due to a bamboo gag and a long "sleep"), but expresses emotions through facial expressions, gestures, and actions: she cries from grief, rejoices when Tanjiro is safe, and furiously rushes into battle if he is in danger.

In Memory of Nezuko Kamado
When Nezuko transformed into a demon, she partially lost her memories—a typical trait for demons in the Demon Slayer Blade universe. Much of her human memory was suppressed, and at first, she acted almost like a child: she experienced many things anew and expressed her emotions more simply.

Yet the key, most powerful memories remained intact: she hadn't forgotten who Tanjiro was, and she retained a deep attachment to her family. Even in her demonic form, she instinctively protected her brother.