Jack Barlowe survived Violet's lightning because he was already venin. Venin can channel enough power within the wards to sustain themselves, even if the barriers limit their greater abilities. Nolon spent months attempting to mend or cure him, which explains the healer's exhaustion and the guarded room. Jack exploits his bond with Baide, kills his own dragon, and destroys the wardstone from inside Basgiath.
Warrick and Lyra recorded different versions of the First Six's ritual because they disagreed about who should possess wards. Warrick's account says six dragon dens and produces Aretia's incomplete shield. Lyra preserves the seventh. Andarna was left behind by a hidden seventh den and waited centuries to hatch when Violet reached the Riders Quadrant. Her camouflaging scales and unique fire complete the ritual.
General Sorrengail's sacrifice is both personal and political. She has spent years defending Navarre's secrecy in the name of protecting her children. At the wardstone she finally chooses their lives over her own authority. Sloane siphons Lilith's power into the stone, killing her but allowing Violet to survive and seven dragons to fire the wards.
Xaden's red eyes mean he has become venin. The Sage had been visiting Violet's dreams all along, and had predicted that love would be what broke someone. When the Sage threatens to kill Violet, Xaden pulls magic directly from the earth. He wins the immediate fight and helps preserve Basgiath, but every act of venin channeling risks consuming more of his soul.
The wards do not reverse the transformation. Jack can live within them, and so can Xaden. Their restored protection therefore solves the military emergency while placing an intimate version of the enemy beside Violet. The central question for the next book is not whether Xaden loves her; it is whether love can survive and restrain a form of power that grows by eroding conscience.