Kyou Kai is a skilled and deadly warrior from the manga and anime series Kingdom. She is a former member of the feared assassin tribe known as the Shiyuu. Despite her initially cold and distant demeanor, Kyou Kai gradually becomes a loyal and trusted ally to the protagonist, Shin, and the Hi Shin Unit. Her agility, swordsmanship, and strategic mind make her an invaluable asset in battles. Throughout the series, she is driven by a personal vendetta to avenge her sister's death, which adds depth to her character and motivations.