Rugal is a recurring boss in SNK's The King of Fighters fighting game series, and is often considered one of the most difficult bosses in the entire series.
On their anniversary website, SNK has stated that Rugal was originally based on the concept of the "mightiest and most evil boss character ever". Like Goenitz and Heidern, his name comes from the anime, Space Battleship Yamato. Toyohisa Tanabe states that his fighting style was created to emphasize Rugal's strength as the series's first boss character. He also comments "going a bit overboard" with Genocide Cutter's damage ratio in The King of Fighters '94.
Feared throughout the political and fighting world, Rugal was an influential arms dealer who operated aboard his aircraft carrier Black Noah. To those who would oppose him, he would defeat them and later preserve their bodies in liquid metal to add to his grisly trophy room. He used to work with his younger brother, but they separated over conflicting interests. When Rugal was about 25 years old, an 18 year old Goenitz took out his eye with one strike and gave him a small portion of Orochi's power for surviving the attack. Since then, he has a bionic eye to replace the one he lost.
Sometime in 1986, Rugal wanted to demonstrate his power in a base at Brazil and murdered everyone he found inside. The sole survivor of the fifty man massacre was Heidern, who lost his right eye during the attack. At the time, he was too displeased with his victim to add him to his "collection" so he deprived the man of his wife and child as compensation. It's speculated that he later regrets this act, but it is never clearly stated.
Before 1994, he recruited two secretaries: Mature and Vice. With their help, Rugal organized a King of Fighters tournament, in order to find worthy opponents. During the invitation phase, Saisyu Kusanagi came to the Black Noah and challenged Rugal. Although Rugal won the battle, he did not subject him to his metal bath. When Saisyu's son, Kyo Kusanagi, arrived with his teammates, he defeated Rugal. Unwilling to accept defeat, Rugal blew up his ship.
Rugal was believed dead, but he used the Orochi power to survive. Replacing his destroyed right forearm with cybernetics, Rugal revived Saisyu, brainwashed him with the help of Vice, and sent out invitations the following year for another King of Fighters tournament. Rugal used an abandoned missile silo as his base in 1995, and abducted the winning team (again, Kyo's team) to fight Saisyu, and then himself. Despite using the Orochi power and becoming Omega Rugal, Kyo's team defeated him. Again beaten, Rugal tried to use more of the Orochi power, but it consumed him. As his body disintegrated, he saw Iori Yagami, who told him that only those "of the bloodline" could control Orochi's power. SNK Wiki