Shield of Thorns: The Thornbound Oath. Book Two, #2

Mist clung to the ancient stones of Eldenkeep like a second skin, as though the castle itself mourned something that had not yet been spoken aloud. In the vault of the Inner Ring, where sacred air rarely stirred and the breath of history lingered thick as incense, silence had become a wound. The pedestal of blackened granite, once aglow with enchantment, now sat bare and cold. The Shield of Thorns-symbol of oath, unity, and sacrifice-was gone.
Not stolen through force or cunning, but spirited away by a will older than any man. The guard who stood watch swore no one had passed him; no alarms had sounded, no doors were breached. And yet, the heart of Eldenkeep had been hollowed out in the dead of night. When the steward discovered the loss, he dropped his torch in horror, sending flames licking up the velvet curtains lining the chamber walls.
The resulting blaze was minor, but symbolic-a scar left to mark the violation. Mage-scribes pored over the broken sigils that had once protected the relic, frowning at the fading echoes of power, mumbling about unraveling wards and shadow-magic. Lady Serelith, Master of Lore, was summoned from the Tower of Glyphs to interpret the shattered spell-lines. What she read there made her face pale and her voice fail.
"This was not theft, " she whispered. "This was invitation." Those who heard her words shuddered, for none could guess what might have been invited in.