He is an egotistical and omnicidal Celestial who desires to expand himself over the entire universe, which would mean the destruction of all life in it. Like Ronan from the first film, this version of Ego is far crueler, more malevolent and a much bigger threat than his mainstream comic counterpart ever was. Not only is he the arch-nemesis of Peter Quill and the rest of the Guardians of the Galaxy, but he is also Quill's biological father, as well as that of his servant Mantis.
He was portrayed by Kurt Russell. Aaron Schwartz was his body double as his younger self. His alternative form was briefly portrayed by David Hasselhoff.