Silver Wall Guardians

Amelina was on watch that night. She was patrolling the inside of the Silver Wall. She knew it was important to make sure that no one tampered with the wall, but in the few years she has been working with the Eternal Guard these patrols found nothing. All she wanted was a pint at the Endless Tankard.
The moons lit the cobblestone path. Amelina looked up to the wall with its lightly glowing sigils. She was amazed by how long this old fossil had stood. A little further down the wall, the outline of a massive humanoid figure was etched into the wall. Amelina was told that they were the Wall Guardian, though she had never seen them in action. She continued her stroll down the path.
Then Amelina heard a scraping coming from the wall. She raised an eyebrow and headed closer to the wall where she was hearing the noise. The scraping got louder and louder until the ground at the base of the wall opened. Shovels poked out of the ground and Amelina immediately recognized the harsh dialect coming from the new hole: Orcs.
The green-skinned warriors climbed from the hole. Amelina and the warriors glared at each other and finally pulled their weapons. Amelina paced backward while several more Orcs crawled out of the hole. A few goblins also scurried out and spread in different directions. Amelina was severely outmatched. She grabbed her horn and blew hard, signaling the other guards.
Before any of them could respond, the massive outline of the humanoid in the wall began to glow. Everyone paused in place as the 20 ft tall stone biped crawled out of the wall. Its arms were more massive than its legs and its upper body was wider at the top. It had a single large stone carved for its head, a glowing sigil in the center of its face.
The orcs gave a battle cry and charged the guardian. The guardian swung and crushed an orc into giblets. Several axes and swords clashed with the guardian putting nicks into its stone surface. Moments later the nicks sealed themselves up, and several more orcs lay dead at its feet. The fight did not last long with the guardian at the ready. However, once the orcs had been destroyed it crept toward the wall.
"Wait," Amelina shouted, "There are still goblins roaming about!"
The guardian did not deviate from its course and slid back into its wall slot. Amelina sighed and ran after the goblins herself. Guess there would still be a hunt tonight.

Utility

The guardians are strictly defense weapons. The Silver Army has attempted to use them for assaults but have failed. It only responds to the presence of Orcs while within the Silver Wall.

Inventor(s)

The runes are evidence that the guardians were created by the long lost Illuna civilization.

Access & Availability

These are publicly visible however the Silver Army restricts the average person from inspecting them too closely for fear of the guardians acting differently than expected.

Complexity

The enchantments put on the guardians are incredibly complex. The challenges of translating the Illuna language are the biggest hurdle of this. At most the magic of the guardians are tied to the magic of the wall.

Discovery

The Guardians were discovered with closer inspection of the Silver Wall.