And there in the dark heart of that underground temple, they stepped deeper and deeper along their journey, guided by some strange pulse of dark energy that radiated within. Dark energy pulsed through the air, guiding them through twisted, turned tunnels in a subterranean world that seemed forgotten under the surface of Eldoria-suffused in a heavy darkness that clung to all like a shroud.
The deeper they went, the more oppressive the atmosphere became. The air turned thick and damp; stone walls were slick with the residue of ancient magic. Strange markings lined the walls, glowing faintly as Aiden passed, and he could feel the temperature dropping with every step.
And in the very center of it, they found it. Which was the Heartstone: a great crystal of pure blackened magic, throbbing with an unnatural light. On a throne of stone, surrounded by the vortex of shadow twisting itself around, as such wrangling the fabric of the world around.
"This is it," Lyra said softly, her voice combining awe and dread. "The Heartstone.".
Aiden moved forward slowly towards the stone. Around it, the air crackled with raw, unbridled power. He stretched out to touch the stone and felt a jolt of dark energy surge through him as he made contact when his fingers knocked against the stone.
Pictures ran across his mind-vision of worlds dying in darkness, civilizations falling to the corruption of the Heartstone. He envisioned himself, not as the Guardian but as part of the stone's being-a creature of shadow and light, lost between two worlds. The darkness was calling him, promising him more than he could ever envision.
"Aiden!" Lyra shouted above his silent, vision-holding trance, "Snap out of it!
Aiden shook his head, feeling the creeping chill of the Heartstone's grasp pull back a little. He turned to Lyra and said with a face stern as stone: "It is more than a stone. A living force feeding on shadows. Twisting shadows into worse."
"What do we do?" Lyra asked, her voice flat.
Aiden scowled. "We destroy it.