Eiichiro Oda outdid himself with a character's backstory in Egghead, which was far more heartbreaking than any other backstory in One Piece.

By the time the story in One Piece reached Egghead, fans had already experienced immense pain through the countless heartbreaking flashbacks. Seeing the characters endure so much suffering was more than enough to make our blood boil. Who knew at the time that the worst was to come? Right from Alabasta, Oda was setting us up for heartbreak with every arc.

Every character in the story has had their fair share of traumatic experiences. And while Suffering shouldn't be compared, the revelation of Kuma's background surpassed anything that came before it. Oda made us go through a whirlwind of emotions with every twist in Kuma's life.

Kuma was introduced as a threat, hunting the Strawhats. All One Piece fans were ready to throw up their hands at the mere sight of the character. As the story progressed, it was revealed that Kuma was the one guarding Sunny during the time jump. It gave us an idea of the depth of his character, we knew there was more to him than just menace. Under Egghead, his past was finally explored. Growing up as a Buccaneer boy, Kuma was forced into slavery along with his family.