Short answers, pulled from the story.
Ares is the Greek god of war and courage, one of the Twelve Olympians and the son of Zeus and Hera. He personifies the physical valor and brutal violence of combat, in contrast to his sister Athena, who governs military strategy and generalship.
Greeks were deeply ambivalent toward Ares because he represented sheer brutality and bloodlust rather than the strategic or honorable aspects of war. In the Iliad, Zeus himself called Ares the most hateful of all gods on Olympus, and Greek myths frequently depict him being humiliated or defeated.
The name Ares is traceable to Mycenaean Greek, where it appears as a-re in the Linear B syllabic script. Walter Burkert connected it to an ancient abstract noun meaning "throng of battle, war," while the traditional etymology links it to the Greek word arē, meaning bane, ruin, or curse.
Cities chained statues of Ares to keep the spirit of war from leaving, treating the binding as a way to retain his protective power. Oracle instructions given to cities in Pamphylia, Lycia, and Cilicia also directed them to bind a statue of Ares annually and put it on trial, with the promise that he would become a peaceful deity and drive away enemies.
Ares was a figure of fear and contempt in Greek religion, associated with savage, uncontrolled violence. Mars, by contrast, was a dignified ancestral protector of the Roman state, revered as the father of Romulus, Rome's legendary founder, and originally an agricultural deity before becoming a war god.
Ares was the progenitor of the water-dragon that Cadmus slew in the founding myth of Thebes. Cadmus served Ares for eight years as atonement, then married Harmonia, a daughter of Ares and Aphrodite. Plutarch records that the plain of Thebes was anciently described as "the dancing-floor of Ares."