Demon fruit beast system refers to a kind of fruit with special ability in One Piece, which can turn people into some kind of animals, so it is called monster fruit. Each demon fruit has different abilities, such as grass fruit turning people into grass, elephant fruit turning people into elephants and so on. These monsters are highly personalized, which makes each pirate have unique combat skills. As time goes by, more and more devil fruits are discovered, which makes the world of One Piece more diverse.

Demon fruit fauna can be divided into different categories. One of them is the animalization system, which can turn people into some kind of animals, such as leopard fruit. The other is animalization, which can make people look like some kind of animal, such as the fruit of a fisherman. There is also a demon fruit that is a mutant line, which enables people to acquire the ability of a certain creature, such as Tianlong fruit.

Demon fruit fauna is widely used. In battle, it can enhance the fighting capacity of pirates and help them defeat the enemy. At the same time, it can also be used in daily life to provide more convenience and fun for people. For example, rabbit fruit can make people travel quickly and long distances, and bird fruit can make people fly. However, the use of the devil's fruit also has certain risks, and once it is used improperly, it may bring fatal consequences.