Collective Power

Collective Power is the four-piece set bonus of the Atheon's Memory armor set from Vault of Glass. While you are affected by any subclass buff, dealing sustained damage to targets creates an Orb of Power. The two-piece bonus, Radiolaria Breach, works alongside it: picking up an Orb of Power grants a temporary Health bonus and a burst of radiolaria fluid the next time your shields break.

The bonus needs an active subclass buff before sustained damage creates Orbs. The set text does not say how many Orbs a single trigger creates, how long the buffs last, or what counts as sustained damage.