Vast crystalline formations covering Aura's surface that chime with every Chroma frequency — the physical architecture of the moon's song and the only place in the galaxy where the full spectrum can be heard simultaneously. Pilgrims who reach their inner chambers risk Ascension or annihilation; Synod harvesters cut them apart for their radiance.
The Resonant Spires
The Spires are not geological formations but something between a nervous system and a cathedral — living crystal that has grown over millennia in response to Aura's psionic field. Each spire vibrates at a specific Chroma frequency. Standing among them is like standing inside a chord that has been sounding since before the first sentient mind looked up at the sky.
The Harmonic Depth
The Spires are layered. The outer ring hums with common, Synod-approved frequencies — the brightness of the Chroma that powers FTL travel and mundane psionic enhancement. Deeper chambers resonate with rarer tones. The deepest spires — the Cored Tones — vibrate at frequencies the Synod has declared forbidden, and simply hearing them unshielded can permanently alter a psionic mind.
The Resonant Order claims to have mapped seven descending "rings" of depth, each exponentially more dangerous. They guard the outer maps and destroy records of the inner ones.
The Cut
The Synod's harvesters operate along the moon's equator in a strip called the Cut — a five-hundred-kilometer wound where spires have been felled and their crystal hauled to orbital refinement stations above. The Cut does not heal. When a spire is severed from the harmonic lattice, its frequency goes silent — permanently. The Dissonant Choir claims each silencing narrows the Chroma's total bandwidth, bringing the Fading Song closer.