Vinsmoke Reiju is the eldest of the Vinsmoke children. She was just three years old when her brothers were born and she had seen her mother and father argue about genetic enhancements. Jude wanted to do genetic enhancements on their sons but Reiju did not understand this till she was much older. After giving birth to her brothers, Reiju’s mother became bedridden and during her final days Reiju visited her and listened to her mother talking about Sanji visiting her. Since she was young Reiju was put under strict training by her father in order for her to get used to their genetic enhancements and develop superhuman abilities. As Sanji was the only one who was unsuccessful in adapting to the training he used to get bullied by his brothers and Reiju used to be on the sidelines. She used to treat Sanji’s wounds and told him that she used to stay silent so that the brothers wouldn't bully her too. When Judge told his children that Sanji passed away (in reality he was imprisoned) in an accident Reiju hid her worry behind a smile while her brothers laughed about it.

During the six months that Sanji was imprisoned, Reiju and her brothers made a lot of progress with their training and their father was proud of them. When her brothers realized that Sanji was still alive and imprisoned they went down there to bully Sanji and later on Reiju used to come to treat his wounds. Once Sanji told Reiju that he wanted to leave the Germa Kingdom and wanted to become a chef, Reiju broke the cell bars and allowed Sanji to run away. Judge disowned Sanji and when Reiju got to know this, she was devastated. She helped him get on a cruise ship and told Sanji that he would meet people who will treat him in the way he actually deserves and told him to never return back to Germa.