Pharaoh Atem

Yami Yugi, known as Dark Yugi in the manga and and Japanese versions, is the spirit of Pharaoh Atem that has been sealed in the  '''Millennium Puzzle and the main protagonist of the original Yu-Gi-Oh series along with Yugi Muto. After Yugi Muto solved the Millennium Puzzle, Yami Yugi resided in Yugi's body and would take possession of it when Yugi or his friends were in danger. After Yugi became fully aware of Yami's existence, Yugi could voluntarily give control of his body to Yami. '''