Ares is a fictional character, a deity appearing in American comic books published by Marvel Comics. The character is based on the Greek god of the same name. He first appeared in Thor #129 (June 1966) and was created by Stan Lee and Jack Kirby. Ares has commonly appeared as an enemy of Thor and Hercules, starring in his own self-titled series in 2006.

Ares, the Greek God of War, was initially depicted as a supervillain, opposing Thor, Hercules and the Avengers. Early on, his influence on Earth was less direct as he created an organization known as the "Warhawks" to create war on Earth. In 2006, the character was recast as an antihero who simply lived for battle, any battle, joining the Avengers as one of their "heavy hitters" with his own "Warriors Honor" codex, versus the one-dimensional villain he had been portrayed as in the past. He would join Norman Osborn's Dark Avengers, believing that he could put his powers to good use, before being killed by Sentry during Siege. He is later resurrected, before returning to villainy and being killed again by the Punisher.

Ares first appeared in Thor #129, 1966, written by Stan Lee and drawn by Jack Kirby. He would often appear as a villain in both Thor and The Avengers over the next 30 years.

A 5-issue limited series, Ares, written by Michael Avon Oeming and drawn by Travel Foreman, was published in 2006 and focuses on this character. Since the release of the Ares miniseries he has been portrayed as an antihero.

Following "Civil War", Ares was invited to join the official, S.H.I.E.L.D.-sponsored The Mighty Avengers, led by Tony Stark, and appeared in that title. He was one of only two members to remain on the team after Norman Osborn took Stark's position, as part of the Dark Reign storyline and appeared in the first Dark Avengers series throughout its run. Ares subsequently starred in a three-issue Dark Avengers: Ares miniseries written by Kieron Gillen. He appeared as a regular Dark Avengers character from issue #1 (March 2009) until his death in Siege.

During "Chaos War", Ares appeared in a one-shot comic titles Chaos War: Ares.

Ares is the son of Zeus and is the Olympian God of War. Ares reveled in war and combat in all its forms, not caring about sides or victims, supporting Troy in the Trojan War. Ares has hated Hercules ever since Hercules killed Ares' pets, the Stymphalian birds, and his hatred increased when he noticed Hercules being favored by their father, while he was shunned for his brutal behavior. Further adding to his hatred is that in modern times, war is shunned and disliked, whereas Hercules is still beloved by the masses despite his own history of death and destruction. As the Romans took on the worship of Greek gods and renamed them, Ares is also the deity Mars.

After Zeus allowed the worship of the Greek/Roman gods to cease, the dissatisfied Ares held a deep grudge and would try to overthrow Olympus more than once. He refused to battle against Pluto on behalf of Hercules, and aided Pluto instead. Hercules teamed up with the Asgardian god Thor to defeat Ares, leading to Ares' retreat. Ares fought a duel with Hercules, forming an alliance with the Enchantress to make Hercules her slave and ally against the Avengers using water from the Spring of Eros, which led to Hercules being exiled from Olympus for a year.