The protagonist doesn't just possess the MacGuffin, they ARE the MacGuffin

1. Leeloo (The Fifth Element)>!is literally The Fifth Element: the key conduit to activating the power to defeat the Great Evil and save the earth.!<

2. Ellie (The Last of Us)>!is the only human immune to the virus, meaning she is the only hope for a cure.!<


3. Denji's (Chainsaw Man)>!heart is a formerly very powerful devil capable of erasing a devil conceptually from existence.!<