Check the latest information for Set 5.5: Dawn of Heroes
At start of combat, the Sentinel with the highest Health gains a shield that grants Attack Speed each time it is applied. When the shield is destroyed or expires it will pass to the ally with the lowest percent Health.
3 200 Shield, +30% Attack Speed, 4 sec duration
6 1000 Shield, +120% Attack Speed, 2 sec duration
9 2000 Shield, +1000% Attack Speed, 1 sec duration