In the Pre-Crisis version of the DC Universe, Ares (as Mars) attempted to provoke a war between the Amazons and the people of Atlantis (WONDER WOMAN vol. 1 #215, 1975). He also recruited a woman named Helena Alexandros to become the warrior called Silver Swan in order to destroy Wonder Woman and murder the President of the United States. He claimed that Helena was his descendant via Helen of Sparta many centuries before (WONDER WOMAN vol. 1 #288, 1982). Both of these efforts failed.
Years after his first encounter with Diana, Ares decided to return to Earth and provoke conflict yet again. Unable to break Zeus’ decree that he not interfere directly, he bargained with a criminal, Ari Buchanan, who agreed to be his human host. The two became Ares Buchanan (introduced in WONDER WOMAN vol. 2 #77, 1993), who, over time, grew to become a formidable crime lord and arms dealer. He used technology from S.T.A.R. Labs to outfit various criminals with advanced weaponry, and his power became great enough that Assistant District Attorney Donna Milton concluded he would never face consequences from the law. She then left her job to become his personal attorney. The two became lovers, and Donna volunteered to go “undercover”—befriending Wonder Woman and acting as Ares’ agent to influence and manipulate her actions (WONDER WOMAN vol. 2 #82, 1994).
Donna Milton became pregnant. Ares initially believed this was a ruse in order to garner Wonder Woman’s sympathy. But soon after revealing his true nature to Diana, he learned that Donna was indeed pregnant with his child. Not caring to have an heir, Ares shot Donna and left her for dead, but she and her baby, Lyta, born that same night, survived. Donna remained Diana’s friend and became her new lawyer (WONDER WOMAN vol. 2 #83-84, 1994). Later, Diana and Ares learned that Donna Milton had actually been the corrupt sorceress Circe, who’d used magic to adopt a new identity (WONDER WOMAN vol. 2 #100, 1995).
Change of Authority
As time went on, Ares and the other gods of Olympus realized their power levels were shifting due to the different beliefs and values held by modern humanity. Some of them adapted to the new age. Yet Ares again decided to focus on manipulating the Amazons and the inhabitants of Olympus. He provoked conflict and events that led to Themyscira’s devastation (WONDER WOMAN vol. 2 #200, 2004). Soon afterward, Athena assumed leadership of Olympus, and Ares killed Hades, taking the realm of the Underworld for his own (WONDER WOMAN vol. 2 #212-217, 2005). Around this time, he also took an interest in (and granted greater power to) Cassie Sandsmark, a daughter of Zeus who’d become the second hero called Wonder Girl.
Rise of the Olympian
Sometime later, Ares manipulated the villains Dr. Barbara Minerva, a.k.a. the Cheetah, and Dr. T.O. Morrow into creating an anti-Wonder Woman from Diana’s own body (retrieved from a possible future timeline in which she died) and the soil from places where genocide had occurred. This warrior homunculus, called Genocide, became a fearsome enemy to Diana (WONDER WOMAN vol. 3 #26, 2009).
When Diana destroyed Genocide, Ares retaliated, sending vicious monsters to attack the Amazons. Rather than see the conflict continue and get any of her fellow Amazons caught up in it, Diana confronted Ares directly and this time killed him rather than try to reason or negotiate for peace yet again. Though she mourned him and felt conflicted about her decision, Zeus assured her it was the right one (WONDER WOMAN vol. 3 #26-33, 2009).
Following the events of 2011’s Flashpoint, Diana’s history was changed so that she was a child of Zeus. Thus, Ares looked on her somewhat protectively, as a brother. When she was a child, Ares trained her to become the fiercest warrior of the Amazons, but was disappointed that she believed in mercy (WONDER WOMAN vol. 4 #0, 2012). When they met years later, Ares had become a tired and cynical old god. Events then led to Diana being forced to kill Ares, at which point the god forgave her for their differences and announced that she was the new God of War.
Recent Events - Rebirth
With 2016’s DC Rebirth, a new history has been written for Diana and some of her pre-New 52 history has been restored. Diana had memories of the New 52 events, but realized these were “lies” that had been planted in her mind in order to steer her away from Themyscira (WONDER WOMAN: REBIRTH #1, 2016).
As before, Diana’s first true battle against the forces of evil was against Ares, who tried to provoke worldwide war through human agents (in this case, a terrorist organization called Sear). But, years later, Diana discovered that the Ares she’d fought throughout her career was actually his children in disguise. The real Ares, initially opposed to Aphrodite, fell in love with her, which cooled his need for war and conflict. He remained a prisoner on Themyscira for centuries and seemed content to remain there (WONDER WOMAN vol. 5 #21-23, 2017). Whether this is the whole truth remains to be seen. For as Diana herself has realized, “Truth is the first casualty of war.”