Otus and Ephialtes were two brothers and giants. The brothers at one point wanted to storm Mt. Olympus. They managed to kidnap Ares and hold him in a jar for thirteen months. He was only released when Artemis offered to sleep with Otus. This made Ephialtes envious and the pair fought. Artemis changed herself into a doe and jumped between them. The Aloadae, not wanting her to get away, threw their spears and killed each other.
One night, while having sex with Aphrodite, Ares put a youth named Alectryon by his door to guard them. He fell asleep and Helios, the sun, walked in on the couple. Ares turned Alectryon into a rooster, which never forgets to announce the arrival of the sun in the morning.
During the Trojan War, Diomedes fought with Hector and saw Ares fighting on the Trojans' side. Diomedes called for his soldiers to fall back slowly. Hera, Ares' mother, saw Ares' interference and asked Zeus, Ares' father, for permission to drive Ares away from the battlefield. Hera encouraged Diomedes to attack Ares and he threw his spear at the god. Athena drove the spear into Ares' body and he bellowed in pain and fled to Mt. Olympus, forcing the Trojans to fall back.
In some versions of the story of Adonis, Artemis or Ares (her lover in this story) sent a wild boar to kill Adonis. This version is suspect because it implies that Artemis had sex with Ares and by virtually all accounts, she remained chaste throughout time.