Create a fantasy Minecraft-style mob called an Aethershard Guardian. It appears when players mine magical Aethershard crystals. Design a creature made of cracked stone plates with glowing blue fissures of arcane energy. A bright Aethershard crystal is embedded in its chest. Add subtle Wyrdroot influences like bark textures, roots, or branch-like horns. Its eyes glow cyan or violet if corrupted by the Umbral Veil. Include drifting blue particles, a mystical forest or cave atmosphere, and a slightly dark, ancient, arcane style.