Navani fails to reach the Sibling, the tower’s spren, and returns to her guarded workroom where Raboniel’s daughter sits vacant-eyed near the door. Raboniel arrives with wine, sharing memories of ancient human arrival and the long fatigue of war. She dismisses peace talks and presses Navani to continue pursuing a method to mix Stormlight and Voidlight.

Discussing tones and rhythms, they compare the pure tones of the Lights and the harmonized nature of Towerlight. Navani posits they need an “emulsifier,” likely sound-related. Using tuning forks and infused gems, she demonstrates how the Lights swirl but won’t mix. Raboniel explains that each Light bears a rhythm and that humans cannot sustain them reliably.

Determined, Navani straps gemstones against her arm to feel the Stormlight’s beat. With Raboniel singing Odium’s rhythm and Navani holding Honor’s tone, they adjust together—softening rather than competing—and physically clasp hands on an empty diamond. Their rhythms align into harmony, and the gemstone fills with an impossible black-blue Light.

Raboniel names the harmony the Rhythm of War and admits she had hoped the Lights would annihilate, revealing her aim to find an opposite capable of killing gods—much as Honor was once slain by unknown means. Navani, recalling Szeth’s strange sphere, realizes Gavilar had pursued anti-Light for the same purpose.

Raboniel pockets the new gemstone and, despite earlier promises, refuses to withdraw from Urithiru. She focuses on securing the tower but allows Navani to continue research or accept other duties. Navani finishes the wine, mind racing with implications as the Sibling remains silent.