77. The Proper Legality

Navani works with Raboniel to discover how to combine Stormlight and Voidlight through harmonic singing, successfully creating a hybrid gemstone. Raboniel reveals she sought this knowledge to understand how Honor was killed, but betrays her promise to leave the tower. Navani realizes her husband Gavilar possessed something far more significant than Raboniel comprehends.

Navani begins the chapter in the tower's library, unable to communicate with the Sibling spren despite her attempts. She attempts to ignore Raboniel's daughter, a mad Fused sitting guard, and continues her work on fabrials. Raboniel visits, bringing wine and discussing the ancient past—her grandmother witnessed humanity's arrival on Roshar thousands of years ago, marked by destruction and burned bodies. Raboniel confesses her exhaustion with the endless war and urges Navani to continue their research, suggesting that understanding the Lights could shift the balance of power. Navani accepts, motivated by scientific curiosity. They discover that Stormlight and Voidlight respond to specific tones and rhythms, each Light carrying its own sonic signature. After initial failed attempts, Navani fashions an arm sheath filled with Stormlight gemstones to amplify her ability to hear and match the tones. By singing in harmony with Raboniel—matching her chaotic rhythm while maintaining an orderly pulse—they successfully combine the two Lights into a single gemstone glowing black-blue, which Raboniel names the Rhythm of War. Raboniel then reveals her true goal: she believed this discovery would teach how Honor was killed, enabling the Fused to gain power over the gods themselves and end the war. Navani suddenly realizes that her husband Gavilar possessed something Raboniel does not—an opposite to Voidlight itself. Raboniel breaks her promise to leave the tower, claiming the security of Urithiru is now her priority. She offers Navani the choice to continue research or take simpler work, and leaves with the black-blue gemstone.