"When a person dies, for most, their spirit enters the cycle of reincarnation," Lan Wangji tells her. "There, depending on their beliefs and actions while living, they may journey to Diyu, the underworld, for judgment and eventually be reborn."

Quiet grief flickers in his glance for an instant, but his tone is ruthlessly calm as he continues. "If a person dies with resentment, they may become an angry ghost. Unless such a spirit can be liberated and set free to rejoin the cycle, they may be lost."