Ken Oba is a minor fictional character from the Japanese adaptation of the Luigi's Mansion series. Portrayed as a ghost researcher, Ken assists Professor E. Gadd with his paranormal investigations. He is known for his quiet demeanor and technical skills, often helping Luigi by providing vital information about the haunted mansion and its ghosts. While not a central character, Ken Oba adds depth to the backstory and supports the main characters in their quest to rid the mansion of supernatural threats.