Immutable Form. The peacekeeper is immune to any spell or effect that would alter its form.
Telepathic Bond. While the peacekeeper is on the same plane of existence as its master, it can magically convey what it senses to its master, and the two can communicate telepathically with each other.
Multiattack. The peacekeeper makes two Slam attacks.
Slam. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit:16 (3d8 + 3) bludgeoning damage.
Calming Mist (Recharge 5–6). The peacekeeper releases a calming gas in a 30-foot-radius sphere centered on itself. Each creature in that area must succeed on a DC 14 Charisma saving throw or become charmed by the peacekeeper for 1 minute. While charmed in this way, the creature is incapacitated and has a speed of 0.
When a metallic dragon grows attached to a settlement of smaller folk—often after dwelling there for a time in Humanoid form—the dragon might decide to create a metallic peacekeeper to protect the place. The peacekeeper can ward a community for centuries, standing in the place of its dragon creator and maintaining peace and order.