Ares was the Greek god of War. He had a miserable childhood as the son of Zeus and Hera - likely because Zeus saw him as a threat to his power and leadership. Ares sister is Athena, almost his polar opposite. You see while Athena represented intelligence in military strategy and generalship, Ares represented the physical, violent, and untamed aspect of war. Ares represented rage.
Ares appeared in Homer's Iliad, presented as a god with no fixed allegiances, - meaning he rewarded soldiers on both sides of any conflict for their courage and ferocity - and no moral compass. This got him into some hot water during the Trojan War. He had promised his sister that he would fight on the side of Achaeans but went back on his word - encouraged by Aphrodite, the only god or mortal who could tame him - and sided with the Trojans instead. This infuriated Athena who went immediately to Zeus and requested permission to drive Ares off the battlefield. Zeus, not caring much for Ares in the first place, obliged her request.
Ares was nearly killed by a spear to the gut, thrust by Diomedes and Athena. Wounded he retreated from the battle.
It didn't end there. In a future battle Ares attempted to return the brutal favor to his sister... but she wasn't having it. She overpowered him and crushed his body with a boulder. Again, nearly killing him.
In the Greek pantheon of gods, gods cannot die. When they are struck down a mist eventually reforms them. Ares never died, but I bet that boulder-whooping by his baby sister shut him up for quite a while.
Of course, Diomedes was later devoured by his horses... but that's Greek Life, right? Here today, eaten by something awful the next.