Character shield
a shield that says the character can't lose a fight that he's in,or if he does,he'll always win in the end.
Watch the Evil Dead movies for the Examples.
Main Character Shield
The invincible shield protecting the main character in a formulaic Hollywood flick.
Oh, he jumped off the Empire State Building holding an orphan while being gunned down by helicopter bullets and hellfire missiles? I'm not even scared he's going to die. He definitely has a main character shield.