TV-Series
Description
Hung Yau is also known as Number 0 or No. 0. He appears in the anime Sacred Seven as a significant figure originating from the same research environment that produced other individuals with the Sacred Seven power. His true identity is that of a Darkstone human, which refers to individuals who have been transformed or corrupted by the power of a Darkstone, a type of crystal that causes a person to lose control and become a monster-like being. Before his transformation and designation as No. 0, his name was Kohaku, which translates to Amber in English.

He is the older brother of the young character Fei Zhui Lau, and this familial connection is central to his role and his tragic nature. Hung Yau is portrayed as a threat, having escaped from the research institute where he was held or created. His primary role in the story is as an antagonist and a force of chaos, driven by his transformed state. A defining moment for his character occurs during an attack on the protagonist, Knight Kijima, who is protecting Fei. In this confrontation, Hung Yau catches sight of Fei. The remaining fragments of his human memories and consciousness surface upon seeing his sister, causing him to hesitate and stop his assault. This single moment of recognition underscores the tragedy of his condition as a Darkstone, where the human mind and will are constantly struggling against the overwhelming, destructive impulses of the power.

His motivations are not driven by malice but are largely instinctual and a product of his corrupted state. As No. 0, he exists as an example of what can happen when the Sacred Seven power is perverted or unleashed without control, turning a human into a rampaging Darkstone. His character serves to highlight the dangers of the anime's central power system and to enrich the backstory of Fei Zhui Lau, connecting her to the very threats she faces. As a Darkstone, his notable ability is his transformed state itself, which grants him immense physical power and durability, making him a formidable enemy. His appearance as a monster is a direct contrast to characters like Knight, who manage to use their Darkstone abilities while maintaining their humanity through the use of a special serum. Hung Yau represents the tragic fate that other Darkstone users constantly struggle to avoid.