The mysterious Hezen Protective is the second major Vex behavioral unit on Venus. Concentrated around the legendary Vault of Glass and the Endless Steps, the site of a massive Vex gate and the access point to the towering Citadel, the Protective's behavior seems very defensive.
But leading Cryptarchs and experienced Guardians warn that it would be a fatal mistake to think of the Vex as a conventional military occupying an area. Vex behavior is always a process, active and purposeful. The Protective is clearly engaged in a colossal project, but as with much Vex behavior, it's unclear whether their ultimate purpose is even comprehensible to us. The Protective may be reacting to an event that has yet to occur, or working towards a goal that - to us - is already historical fact.