From Guild Wars 2 Wiki
“Surround yourself and nearby allies with a shield. Damage foes that strike protected allies. Grant protection to yourself and nearby allies if you are not struck.
— In-game description [?]
- Blocks the next attack directed at any ally within the shield and counterattacks all surrounding enemies, ending the shield.
- The animation that grants protection if you are not struck is a Combo Finisher: Whirl, though this is not listed in the tooltip.
- A Guild Wars skill bears the same name as this skill.