One of the three children of the supreme Greek Olympian Gods, Zeus and Hera, Ares is the God of War, loving battle for its own sake. Ares never favours one city or party over another, fighting on either side, as inclination prompts him, delighting in the slaughter of men and the sacking of towns. Despite being Zeus' son, Ares never fit in with the other gods of Olympus and created his own realm, the Areopagus. Ares is hated by all his fellow immortals, from Zeus and Hera downward, except for Eris, and Aphrodite, who nurses a perverse passion for him, ultimately bearing his children, Deimos, Phobos, and Harmonia.
In DC Comics:
Ares is a recurring antagonist of DC's flagship superheroine Wonder Woman.
Over the years, his appearance has varied per writer fiat. In his Golden Age appearances, he often appeared as resembling a powerful Roman Legionare and went primarily by Mars rather than Ares.
George Perez re-imagined Ares after the Crisis on Infite Earths as a towering dark knight in blue plate armor, often only revealing his red eyes through the slits in his helmet, at other times revealing a demonic face hiding beneath the steel. He would later appear as more human, first as a ploy where he possessed a mortal and later revealing that while on Olympus he normally appeared as a scarred blond. Finally, after he became the ruler of Tartarus and seemingly slain by Diana, he appeared to be paling while crude stitches was had been used to bind his wound.
In his New 52-guise, Ares bears an uncanny resemblance to the writer Brian Azzarello as he had asked Cliff Chiang to draw Ares as a tired old man. Perhaps to reflect his own mood or the state of the idea of War, he appeared as a physically imposing, bald warrior with a long red beard and dark pits where his eyes should have been when he first appeared before a young Diana. When she rejected his ways he withered away into a dry old man in a sand coloured suit that always has blood on his shins and feet. As with all Olympians, he rejects the use of any kind of footwear.
Though wielding considerable power in the post Crisis world, so much in fact that not even Diana can physically threaten him save with certain items, Ares' true strength is his ability to scheme and manipulate from his home of Areopagus. He has come into conflict with Diana on numerous occasions as well as her allies Donna Troy and Cassandra Sandsmark along with others like Batman and his allies and the New Gods.
His perhaps greatest feat came near the culmination of the Genesis event, where he appeared and slew Highfather of New Genesis before attempting to gain control of the Godwave only to become stuck in the Source Wall. Often he is also considered the direct or indirect reason for both the Amazon's existence and later isolation on Paradise Island. Chiefly as they were created to combat his influence in the world of men and later it is his influence that spurs Heracles (or Hercules) to attempt and succeeding in enslaving the Amazons.
Post-Flashpoint, the character has been reinvented such that his relationship with Diana is more akin to that between a father and daughter. While Diana was young, Ares appeared before her and offered to train her during the full moon's light. Unknown to Diana, Ares was doing so because in Diana he saw his successor. The two suffered a split after a year when Diana refused to be merciless, even if Ares had been the same previously. Ares was to have spent the next 15 years in a disillusioned state, caring nothing for his mantle or his family while drinking his problems away. This only seems to change slightly when he is reunited with Diana, during her efforts to keep Zola and her child safe, first from Apollo and later the First Born. In a final fight with the First Born, Ares allows himself to be killed, allowing Wonder Woman to take his place as god of war as he intended.
In Marvel Comics:
Ares usually appears in the stories of Marvel's other myth-based heroes Thor and Hercules. After living the life of a god for millenia and tiring of it, he decided to live a normal life on Earth as a carpenter with his young son, Phobos. While on Earth, he fought on the sides of both good as well as evil, being a member of Tony Stark's Mighty Avengers as well as Norman Osborn's Dark Avengers. During the siege of Asgard, Ares was brutally murdered by one of his own teammates, an out-of-control Sentry. He was briefly reanimated by Amatsu-Mikaboshi, the Chaos King, before returning to Hades following Mikaboshi's defeat.
For more information on Marvel's God of War, visit the Ares page.