Ares was the first god of savage warfare, with his sister, Athena, presiding over military strategy. Called upon by the Spartan general, Kratos, to aid him in a battle gone terribly wrong, Ares agreed in exchange for the mortal's oath of servitude. Ares fulfilled his end of the bargain, destroying the barbarians who fought against the Spartan forces, and granted Kratos the Blades of Chaos as a gift.
Under Ares' service, Kratos led Sparta to conquer much of Greece. However, during one battle, blinded by bloodlust, Kratos killed his own wife and daughter. Although Kratos was grief-stricken, this was all part of the god of war's plot: He saw Kratos' family as hindering his champion's progress, and had led Kratos to their village in order to kill them. Kratos swore revenge, and left Ares' service.
Kratos' chance for revenge soon came, as he was sent by Athena to prevent Ares' attack on Athens. The only way for Kratos to kill a god was to use the power of Pandora's Box, hidden in the Temple of Pandora on the back of the Titan Cronos. Kratos retrieved the Box, but Ares caught on to Kratos plan, and killed him before he left the Temple.
Breaking out of the Underworld, Kratos regained the Box and used it to meet Ares in battle in the harbor outside Athens. Ares unleashed his full power, taking back the Blades of Chaos and almost driving Kratos mad. However, at the last moment, Kratos took up the powerful Blade of the Gods and impaled Ares with it, killing him and taking his place as the god of war.
Battle vs. Loki (Comics) (by CuchulainSetanta)
In the forests of Norway, Ares treads through, preparing to invade Asgard. Loki sees this and heads down, unwilling to allow another god to take over the realm he has his own ends for. Loki magically boosts himself to Ares' hight, surprising the god of war. Ares summons his sword and prepares for battle, while Loki charges up his magic.
Ares charges forward, blocking a magic bolt hurled at him by Loki. As Ares swings with his sword, Loki teleports behind him, blasting Ares in the head with another bolt. Ares extends his blades from his back, swinging at the god of mischief, but again, Loki teleports away.
Ares looks around, confused about where Loki has gone. Hearing something, Ares looks in the direction of the noise and sees Loki lifting a massive boulder to throw at him. Loki flings the boulder, but Ares easily ducks under it. Loki summons a spear, and leaps in to do battle. The two gods clash, until Ares starts getting the upper hand. He knocks Loki back, before unleashing a firestorm which burns Loki to cinders.
Ares laughs to himself as his enemy falls dead, but as the fire clears, "Loki" suddenly reverts to its true form: a boulder. Ares turns to look at the boulder from earlier, just in time to get stabbed through the neck by the true Loki. Ares falls to the ground and explodes, with Loki summoning a force field to protect himself. The smoke clears, and Loki sees Ares has been destroyed. Satisfied, Loki teleports away, cackling.