From Destinypedia, the Destiny wiki
Lighthoarders are a unique variant of Hive Knights and Wizards found in the PsiOps Battleground activities. They appear next to Lucent Beacons, where they gain an immunity shield until the beacon is broken. In each mission, 3 Lucent Beacons exist, and once each one is broken, the Lighthoarder will begin to move to the next one. After the final beacon is broken, the Lighthoarder will eventually despawn. Upon killing one, a Lighthoarder will drop Hoarded Light, a currency which will automatically redeem at the end of the activity, giving the player extra rewards.
List of appearances