Superior Defender

Superior Defender is a perk added to Fallout 3 in the Point Lookout add-on.

It provides a bonus of 5 to damage and 10 to armor while standing still. This perk is extremely useful to a Sneak based character, most of whom will have a tendency to sit still lining up shots.

Obtaining
The Superior Defender perk is earned upon completion of The Local Flavor quest.

Trivia
Obviously the the icon of the perk is a reference to the movie 300 (although a highly inaccurate movie), or simply Spartan Warriors in general.