All lifeforms have the Lineage Factor, and by manipulating it from a young age the growth of a lifeform can be changed. Eating a Devil Fruit affects one's lineage factor that allows them to gain a supernatural power.
By manipulating the Lineage Factor, Vinsmoke Judge was able to create enhanced humans, specifically his five children. The subjects develop an Exoskeleton (外骨格 Kaikokkaku?) and, with training, rapidly increase in strength and resilience to the point equaling an adult man while in their early childhood. However, Judge found out that the process can have its failure rates, as Sanji remained as a normal human despite modifications.
Vinsmoke Judge conducted several researches and experiments with the Lineage Factor, becoming able to artificially manufacture human beings to fill the soldier ranks of Germa 66. Those soldiers are known as Clone Soldiers (複製 (クローン) 兵 Kurōn Hei?) and they are made without the knowledge of their origin.
- The Lineage Factor is a reference to DNA, the molecule that contains all the genetic information of the host organism.
- ↑ 1.0 1.1 1.2 One Piece Manga — Vol. 84 Chapter 840 (p. 3-5), Yonji explains the Lineage Factor and cloning.
- ↑ 2.0 2.1 One Piece Manga and Anime — Vol. 70 Chapter 698 and Episode 625, Law explains that Caesar's research is an application of Vegapunk's genetics research.
- ↑ One Piece Manga — Vol. 84 Chapter 841, Reiju tells Sanji that his three brothers don't have certain emotions.