Ares was one of the 12 Olympians & son of Zeus & Hera. He represents the physcial or violent & untamed aspect of war & is the personification of sheer brutality & bloodlust.
He has a limited role in Greek Mythology. When he does appear, he's often humiliated. Aprophrodite persuaded him to take the Trojan's side in the Trojan War - they lost; when Hephaestus finds his wife Aphrodite is having an affair with Ares, he traps them in a net & exposes them to the ridicule of the other Gods. (No wonder he was always ticked.)
His nearest counterpart is the Roman God Mars who was treated much better & given an important & dignified place within the Gods. Mars secured peace while Ares reveled in war.