Haki is a special ability in the world of One Piece, a popular manga and anime series created by Eiichiro Oda. It allows individuals to sense and manipulate spiritual energy for various purposes. There are three main types of Haki: Kenbunshoku Haki, which grants the user heightened perception; Busoshoku Haki, which enables the user to create an invisible armor or enhance attacks; and Haoshoku Haki, which allows the user to exert their willpower over others. Haki is essential for combat in One Piece, especially against powerful foes who possess Devil Fruits. While not everyone can use Haki, those who train can develop their abilities over time. Characters like Monkey D. Luffy and Roronoa Zoro showcase the importance of Haki in their battles, making it a crucial element of the series' lore and action.