Ares was the God of War of the Greek pantheon of gods and a villain in Hercules: The Legendary Journeys, Xena: Warrior Princess, and Young Hercules. He is the main antagonist of the Hercules and Xena franchise,and the arch-nemesis of the two protagonists.
He was portrayed by the late Kevin Smith.
Battles against Hercules
He appeared as a monster who was simply known as the Ares Monster but later on he adopted a human form which he kept. He would often challenge Hercules since he was a teenager. He would get to him through his mother, his friends, and the mortals he would protect.
His Obsession with Xena
He was also hopelessly obsessed, perhaps even in love, with Xena, a warlord turned heroine to the masses. Since Hercules redeemed her, she swore to never give into Ares' lies and deceptions. Ares once joined the dark evil god known as Dahak and was mated to his daughter, Hope, the demi-goddess who resembled her mother, Gabrielle, the Bard turned Amazon Queen who was Xena's best friend. Together, they brought forth a demonic child known as the destroyer.
Twilight of the Gods and becoming Mortal
Later on before the Twilight of the Gods, he would kill Eli, the messenger of the God of The Light. That act only made him both an Angel and a martyr. Shortly after, it was revealed that Xena's child would be the bringer of the Twilight, so the other gods of Olympus tried to have her killed, except Ares who wanted to make a deal with Xena; he would protect her, her daughter, and Gabrielle, provided that she would be with him. She refused and faked hers and Gabrielle's deaths. Ares would bury both women and said to her that when she loved, that she was Gabrielle's but when she "kicked ass" she was his.
Over the course of 25 years, Ares would raise Eve not knowing she was Eve as the Roman Warlord, Livia. But then when Xena returned, it was revealed she was really Eve. After Xena redeemed Eve, all of Olympus rained down their fury on them, but it was revealed that Xena had the power to kill gods. Ares would still try to make a deal with Xena, but she refused. She would eventually kill most of the gods. However, Ares would give up his immortality to save those Xena loved, being Gabrielle and Eve. He would for a time become mortal.
When he became mortal, the furies would possess him, drive him mad, made him hurt Xena. But then when the furies were killed and Xena would be saved, Ares went out to find himself a new purpose. He would help Xena save his sister, Aphrodite, the Goddess of love from the insane Caligula. Though his sister would become mortal. Xena and Gabrielle would discover that he has a bounty on his head from every warlord throughout the known world. They hid Ares in Xena's childhood home which was a barn.
Return to Godhood
Later on when the world was without love, he and Aphrodite were restored back to becoming the Gods of Love and War. Ares would later on lament over a post-Twilight Olympus and how it wasn't the same and a bit empty and hollow. He would later on return to his war god ways and seduce and Amazon Queen, but Xena exposed him and allowed the Amazon Queen to see him for what he was. However, in the end, Ares and Xena came to a degree of understanding that one will never be able to change the other.
Ares was for some unknown reason trapped in a tomb. He was awakened by Janice Covington (Gabrielle reincarnated) and Melinda Pappas (Xena reincarnated). He had plans to re-assert himself as the God of War. He wanted to use Adolf Hitler to help him ascend not only back to his former glory, but to ascend higher than he ever did. However Melinda, who temporarily got the spirit of Xena in her, and Janice stopped his ascension and trapped him in the tomb.
The 21st Century
Ares would once again return, this time wearing a trench coat and drive a motorcycle and try to put a claim on Xena that he made back when he married her two thousand years before. But the current day incarnation of Xena once again stopped him.