Shinobu Kocho is one of the major supporting characters in Demon Slayer. She is a Demon Slayer in the Demon Slayer Corps’. Shinobu was also an Insect Hashira. She is also one of the most underrated characters.
Personality
She is a comparatively cheerful person. She loves to smile despite the conditions of the situation. Yet, this trait is not always likable. She used to tease people to an unbearable extent.
Giyu Tomioka was one such victim of sadistic teases. However, no matter how chilled and easy-going she was, she still showed fierce strength in fights. Initially, she did try to get along with Demons.
But, she was superb when she killed Daughter Spider Demon.
Basically, Shinobu gave her hopes that she can help her; she also attempted to kill Nezuko. However, she showed deep compassion for both Tanjiro and Nezuko. It was after she heard their heart-wrenching story.
Later, we all knew that her cheerful nature was just an upper mask on her deep scars. Shinobu hated the Demons. Due to the loss of her sister Kanae, her parents, and her seniors at the Butterfly Mansion. Her hatred was deep and strong.
Tanjiro did sense this anger when they were conversing. Shinobu had a deep desire to get revenge. This feeling spoiled her entire life. Hence, she gave her everything to win against the Demons.
Childhood & Problems

During the fight with Doma, Shinobu said that she is suffering from an inferiority complex due to her physical traits. She also revealed that she gets jealous quite easily.
The jealousy was towards her fellow Hashira, who were comparatively taller and had muscular bodies. This benefitted them in combat.
In her childhood, Shinobu was quite straightforward and blunt. She had a negative approach towards Kanao Tsuyuri. However, after her own sister Kanae died, Shinobu’s life changed. She became more like Kanae.
Just like Kanae, she possessed the same serene smile. Shinobu even learned to manage her anger. Even though it was not shown on the screen, Shinobu had a bad temperament.
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