Kaidou’s rise to power began as a promising child soldier in the Vodka Kingdom. Against his will, he was drafted into the Marines but managed to escape, marking the beginning of his career in piracy. His strength and potential caught the attention of Edward Newgate (Whitebeard), who invited him to join the infamous Rocks Pirates as an apprentice. During his time with the Rocks, Kaidou formed a bond with Charlotte Linlin (Big Mom) and played a role in their exploits until the crew’s defeat at the God Valley Incident.

After the Rocks Pirates disbanded, Linlin gifted Kaidou the Mythical Zoan-type Devil Fruit, the Uo Uo no Mi, Model: Seiryu, which allowed him to transform into a massive azure dragon. With this newfound power, Kaidou founded the Beasts Pirates and built them into a formidable military force. He was later invited to Wano Country by Kurozumi Higurashi, where he allied with the shogun, Kurozumi Orochi, and established Onigashima as his base of operations. For two decades, Kaidou ruled over Wano, using its resources to strengthen his army and advance his ambitions.

Kaidou is an imposing figure with a towering, muscular build that underscores his immense strength. His long black hair, prominent mustache, and numerous scars from past battles add to his fearsome presence. He often appears shirtless, highlighting his tattoos and battle-hardened physique. Wielding a spiked kanabo, Kaidou embodies raw power and brutality. His Mythical Zoan Devil Fruit allows him to transform into a massive azure dragon, further emphasizing his terrifying appearance.

Kaidou is a ruthless and power-driven individual, valuing strength above all else. He has little patience for weakness and expects absolute loyalty from his subordinates. However, his nihilistic outlook often leads him to moments of frustration and despair, as seen in his heavy drinking and mood swings. Despite his cruel nature, Kaidou respects those who demonstrate exceptional strength or resilience in battle.

Early Mentions
Kaidou was first referred to during the Post-Enies Lobby Arc by Monkey D. Garp and later mentioned in the Thriller Bark Arc by Gecko Moria, who revealed Kaidou’s role in defeating his crew.

Control Over Wano
Kaidou allied with Orochi to establish control over Wano. He defeated Kouzuki Oden and crushed the rebellion led by the Nine Red Scabbards, securing Wano as a strategic base for his operations.

Alliance with Big Mom
Kaidou’s alliance with Big Mom aimed to secure the Ancient Weapons and challenge the World Government. Despite their partnership, their relationship was strained due to their history as former Rocks Pirates.

Raid on Onigashima
During the Wano Country Arc, Kaidou faced the Ninja-Pirate-Mink-Samurai Alliance in a climactic battle. After a prolonged struggle, Kaidou was defeated by Monkey D. Luffy, marking the end of his reign and the dissolution of the Beasts Pirates.

• Yamato
  Kaidou’s child, Yamato, rebelled against his authoritarian rule and embraced Kouzuki Oden’s ideals, creating a strained and hostile relationship.

• Charlotte Linlin (Big Mom)
  Kaidou’s former ally and fellow Rocks Pirate. Despite their partnership, their rivalry and mutual distrust persisted.

• Monkey D. Luffy
  Luffy became Kaidou’s ultimate adversary, defeating him in the Raid on Onigashima and ending his rule as an Emperor.

• Kurozumi Orochi
  Kaidou initially allied with Orochi to gain control over Wano but later betrayed and killed him during the New Onigashima Project.