Rot does not negate life; on the contrary, it is the closest to hope in all Blood Cities. After all negative emotions and despair decay, something new is born. Decay is the first step into the cycle, a process of release and rebirth.
The truly terrifying power of the Rotting Blood City isn't decay; it's an endless cycle of evolution. Whether in the Deep World or the real world, nothing is eternally unchanged. Everything ends, and everything begins anew, fate included.
Thirteen Blood Cities represent thirteen different rules and thirteen poisons that can threaten fate. Decay is one of them.
The memories shared with Gao Ming by the Flesh Immortal are all related to the Rotting Blood City. That Blood City also has two masters; one represents decay, the other new life. Decay roots itself in the Deep World, while new life reaches all people.
