Doctor Katsuhiro Stingray is the father of Sylia and Mackie Stingray in the Bubblegum Crisis series. He is also the man responsible for inventing the bio-synthetic androids known as Boomers. His goal in life was to create a Boomer capable of free thought and action, one that could live alongside humans not as a tool but as a friend and ally. However, the GENOM Corporation saw Dr. Stingray's invention as an instrument to be exploited so that they might be able to gain power and control over society. They arranged for Brian J. Mason to assassinate the doctor and commandeer his research. With Katsuhiro dead, Sylia and Mackie were orphaned and GENOM marketed Boomers to the public. Since then, there have been others hoping to continue and complete Dr. Stingray's work, and Sylia would be spurred into forming the Knight Sabers to battle against GENOM.