Chapter 840

Chapter 840 is titled "Iron Mask".

Short Summary
Yonji reveals to Sanji that the Germa 66 soldiers are all clones, who were created by the duo of Judge and Vegapunk. Ichiji and Niji then enter the room, and Sanji attacks Niji for beating Cosette. However, Niji retaliates and quickly overpowers Sanji.

In the Vinsmoke children's early childhood, they were revealed to have been born through genetic manipulation, and were trained to lead the forces of Germa 66. However, Sanji failed to develop while his siblings continually outpaced him, causing them to bully him. Eventually, Judge put an iron mask on Sanji and locked him in a dungeon forever to erase his existence.

Chapter Notes

 * It is revealed that Judge and Vegapunk used to be partners until Vegapunk was arrested for discovering the blueprint of life.
 * It is revealed that Sanji and his brothers were bred in a laboratory, but Sanji was considered a failed specimen.
 * The soldiers in Germa 66 are cloned humans.
 * Sanji attacks Niji but is once again knocked down.
 * In the past, Judge abandoned Sanji in a dungeon and claimed that he died in an accident.