Caster nodded slowly. "Ah yes. Young fires, fresh from the sun. Of course they're joyful, being new to this world. I do not resent them for it."

He dropped a heavy stick onto his fire; it flicked low, half-smothered, as the tendrils tried to reach up and into the wood.

"But this is an old fire," said Caster. "And it remembers what it was used to do."

He ran his hands through his hair. "I was there when it all began, you know? Not when man invented fire, but when he learned to flay it. It became possible to carve away the heat and the smoke and get to fire's purest essence, the raw force of it. We thought that we were purifying it, removing the choking ash and the corpses of fossilized trees, letting it free into the world to shine as beautiful as reason. But, as you observe, we'd also cut away the warmth of it. I lived long enough to see a world where fire no longer breathed, where it ran through the world as a corpse. That's why I'm not surprised by this place. Like a single seed grows into a tangled seringueira, so every corridor and pit here was contained within the spark we used to illuminate the world."