Not Pressing A Directional Button Towards Your Opponent And Pressing The Right Bumper Starts A Fatal Rush.
This Can Be Blocked, Some Can Be SideStepped.
Most Do Roughly 10-15% of Max Health If The Hit Connects.
Mashing Right Bumper Some More Continues The Fatal Rush, And It Will Continue Until It "Ends" Or If You Have Enough "Special Gauge" It Will Combo Into A Break Blow!
Good Luck!