Designated as the Waters of Truth, this fluid was concocted by the Kouhun, a clandestine organization taking its moniker from a being of the same designation, for utilization in rituals. The creation of this liquid involved a multitude of components, notably poison derived from a kouhun, and it was stored within the Necropolis located in Mataou. Individuals aspiring to membership within the Kouhun were required to consume a portion of this fluid as an integral component of their initiation process, remaining unaware of its significant toxicity until the ceremony's completion. If left untreated, the consumer's body would undergo a gradual deterioration. Spanning several weeks, the individual would experience substantial debilitation, affecting both their physical and cognitive capabilities. Nevertheless, the Kouhun society would provide an antidote to those candidates who successfully endured the initiation trials while the poison circulated within their systems. The Nightsisters also employed this substance.