The Hive are a race of undead magical insectiod aliens that work for The Armada and are lead by Crota and as a result, also Oryx. They were the first part of The Armada to land on the moon, spearheaded by an avatar of Crota crashing into the moon, resulting in a crater that would act as The Hive's main breeding ground in their attempt to raise an army to attack Earth. Their hierarchy (from highest ranking to least) is as follows:
Pieces of Crota and The Blood of Oryx
Some parts of The Hive take direct orders from Crota and Oryx. The Blood Of Oryx acts as his elite guard as well as personal strike team, and are often used as backup for The Taken.
The Pieces of Crota are similar to The Blood of Oryx, except there are three main differences.