Warden X-7

Ecology
Warden X-7 is a massive, sentient Adamantine Clockwork golem designed to be the ultimate guardian for the Deep Vaults of the Grand Arcane Bank. It is the pinnacle of Kigum's defensive engineering, possessing a rudimentary intelligence that allows it to analyze and counter the tactics of intruders.
Combat Mechanics
Warden X-7 is entirely immune to all magic of 5th level or lower. It has an "Adaptive Protocol" that allows it to gain resistance to the last damage type it received. It attacks with two massive adamantine hammers and can unleash a "High-Gravity Pulse" that pins all enemies in a 30-foot radius to the floor, reducing their speed to 0 and dealing 4d6 bludgeoning damage.
Loot
The golem's body contains several hundred pounds of "Adamantine Gears" and a "Master-Key Spark." The gears are invaluable for master-tier crafting, and the spark can be used to bypass any door or lock within the Grand Arcane Bank.