Sebastian's eyes flashed white as Clary drove the last strike against his chest.
"There," she breathed, "It's done."
Jace let Sebastian's still body slither to the bed, the boy's figure visibly heaving for oxygen, his eyes dimming.
"What's happening?" Jace murmured.
"It's a cleansing rune," Clary said as she watched her brother gasp for air, "It's meant to restore the good in someone. There's too much evil in my brother; there's not enough good left to sustain life."
They both watched as Sebastian took his last breath. Jace took Clary in his arms. It was over. It was finally over.