A violently pulsating black sphere inside Gu Chenran's chest, beneath the Binding Seal. It is the heart of an ancient sorcerer who practiced dark arts with formidable Cultivation Base. It constantly attracts vengeful spirits and allows them to invade his consciousness and body. It was likely implanted when Gu Chenran was eight years old during a seven-day unconscious period. It grows stronger over time and is more powerful than Wen Ling, making it impossible to remove currently.
