Damage Shields are pools of additional health that take damage before Health is reduced. There are two types of shields: Bullet Shields and Spirit Shields, each of which blocks only the respective damage types. Damage Resistances do not apply to shields. Once damaged or fully depleted, they will fully recover after some time.
If not fully depleted, a shield will begin recovery if it has not been damaged in the past 20 seconds. This countdown will be interrupted by taking damage.
If fully depleted, a shield will begin recovery after 50 seconds regardless of whether the player has taken the respective damage type recently. This recovery will persist for a few seconds even after the player has taken damage.