Resonance Sentinels

The Sentinels are massive, obsidian-like obelisks embedded directly into the sunstone of the Great Wall. They are not merely placed on the wall but are seamlessly integrated, with the wall's magical veins connecting directly to the Sentinels' cores. Each Sentinel is a living node in the city's magical circuit, drawing power from the Grounds in the Verdant Expanse and filtering it. They take the raw, stabilizing energy and project it outwards as a powerful, shimmering forcefield—the primary ward that keeps the Void's corruption from seeping into Haven.   This constant process is both visible and audible. The Sentinels do not merely stand there; they emanate a low, rhythmic thrum that can be felt by anyone on or near the Great Wall. This sound is the aural signature of the city's magical defenses at work. Their glowing cores pulse with a steady, soft light, which intensifies and changes hue to a flickering, desperate red when the Void's pressure increases.   The Sentinels are in a state of perpetual magical combat, constantly fighting against the Void's chaotic static. This constant strain makes them vulnerable to damage. If a Sentinel is overloaded or begins to destabilize, the forcefield it projects will weaken, and a crackle of static will emanate from it, warning the city's protectors. When this happens, a Conduit and their bonded Charges must be dispatched to the location to perform a "Resonance Re-Calibration." This is a difficult and dangerous magical procedure that involves the Conduit channeling their own energy to re-attune the Sentinel's core, a delicate process that risks magical backlash.  

Original Purpose

Like the wall itself, the Sentinels' original purpose was not to protect a civilization, but to serve as a high-powered magical firewall. They were designed by the wizard to be sophisticated energy filters, allowing the benign magical current from the Verdant Expanse (which at the time was simply his cultivated garden for his O'che experiments) to pass through, while blocking any chaotic magical interference from the outside. They are, in a sense, the city's immune system, a complex part of the containment field that has since been repurposed for the defense of the civilization that grew within the wizard's cage.