Ares was built in 3436 and designed as the one hundred and seventieth and final model of Nega's N-100 Series robots, specifically made for combat against Nega's greatest enemy, Imperial-Princess Blaze Kojo the Cat. But he wasn't activated until a year later and had been left in storage for all that time.
After reactivating the war machine in the Negadome's storage room in the ruins of New Megapolis, Nega gave Ares his first mission to hunt down and destroy N-160 Apollo. At first, Ares refused his mission as Nega had left him in storage for over a year and he was built to destroy Blaze the Cat, but his mission was to destroy something else. The doctor informed Ares that he alone would kill Blaze and threatened to put him back in storage for a decade if Ares did not follow orders. Ares then left to begin his mission as Eggman Nega and Eve watched him leave from the landing bay of the Negadome, leaving his master to his final battle with Blaze that would lead to his fall into insanity and Eve and the Web Queen's coup d'état on the Nega Nation.
After locating N-160 Apollo in the remote mountains hours later, Ares was forced to battle the rogue robot as well as G.U.N. agent Caput Mortum. Delighted to fight an opponent stronger than Blaze, Ares focused on Caput until Apollo fired at him and Ares realized that his mission objective was there too. Caput then attacked Ares and told Apollo to get to the extraction point while he distracted Ares. Intent on completing his mission, Ares temporarily disposed of Caput by using his arm cannon to capture and blast him away. Ares then chased after Apollo and exchanged monologues via radio. While Ares stated how he was superior to Apollo in every way, Apollo pointed out that Ares' superiority had downsides that could be used to his advantage, and that his own downsides that Ares pointed out were advantages for him as well. Eventually, Apollo admitted he was outdated, just as Ares said and that the resistance forces would need something more than him to fight the Nega Nation. Accepting this as surrender, Ares prepared to give Apollo a "glorious destruction" by unleashing all his weapons on him at once out of respect. Telling Ares his soul will remain even if he is destroyed, Apollo uploaded some of his programming into Ares before his robotic body was destroyed by Ares' barrage. A red Flicky then flew away from what remained of Apollo afterwards, while Ares became overwhelmed by his new programming and free will.
Gaining Free Will and Joining G.U.N.
After Caput arrived seconds after N-160's destruction, "Apollo" spoke through Ares, informing them that he uploaded his coding into Ares. The coding integrated into Ares and the two entities became one. With a new feeling of purpose, Ares was convinced by Caput to join G.U.N. and fight against the Nega Nation like Apollo would have, and to also get his revenge on Nega for keeping him in storage and wasting his potential. After Ares created a grave marker made out of rocks for Apollo, he and Caput were picked up by a G.U.N. helicopter and brought back to G.U.N. HQ where Ares met Commander Bastion, who considered Ares as an excellent "replacement" for Apollo. Ares was then examined by Faith Agen, who was amazed to find out that half of Ares' body weight was in ammunition, jokingly calling him a "monster" when she discussed the examination with Caput and Aliz in the recreation room later on.
Member of Team Dark
After Caput and Aliz failed to obtain a Sol Emerald from Feist in the Special Zone, Caput engaged in some violent training in G.U.N. HQ's gym with Ares, who noticed Caput was "agitated" due to him wanting to fight Ares on his own instead of Ares starting it as usual. Ares said that Caput should not let his failure concern him, as Ares had been cleared for active duty and would accompany Caput and Aliz on their next attempt to obtain an emerald in the Special Zone, saying they'll have an advantage with him because he will "blast" Feist, angering Caput to which he knocked Ares to the floor. Ares was then left wondering if it was something he had said as he watched Caput leave the gym. After some discussion with Faith, Caput was convinced by her that they would be better prepared for Feist next time and he then went to the Special Zone again with Aliz and Ares as part of the newly formed Team Shade. Upon arrival, Ares immediately wished to consume both the Zone and Feist, who had called him a "tin soldier", with "fire", but Caput denied him permission for the former, and told him to "get in line" for the latter. Ares and the rest of Team Shade were then given a new challenge by Feist; to retrieve the Sol Emerald from the centre of a cube-shaped maze. They found the emerald above a floor of spikes, but failed to retrieve it in time as Feist encased it within a wall of multi-coloured gems which they failed to penetrate in time. Feist then teleported Team Shade and the emerald out of the maze and began to mock them. The trio then initiated "Plan B", much to Ares' pleasure. Ares, as part of the plan, attacked Feist with his weapons full in the face as a distraction while Aliz and Caput stole the emerald from the zone's master. Feist became enraged by this, but Team Shade escaped thanks to Caput's use of Sol Control that had been enhanced by the power of the Sol Emerald, much to Ares' displeasure as he had five salvos left. Ares and the two Mobians then returned to G.U.N. HQ, and Aliz complimented Ares on his work, earning an embarrassed look from the robot who said it was "only a small megaton of ordinance". Caput then gave Commander Bastion the Sol Emerald, who was more than satisfied with their success at making G.U.N. an even greater "force to reckon with".
Ares is described as being a "walking arsenal" due to being equipped with over four dozen forms of weaponry mainly concealed in his arms (somewhat similar to that of Omega) and upper body. His armoury consists of rapid-fire machine guns, flamethrowers, lasers blasters, missile launchers, cannons and many more weapons, giving him "more firepower than the entire old Neganik horde combined." He has also displayed considerable physical strength, making him capable of destroying thick trees by either smashing them with his metal fists or using his claws to slash through them. Ares also tends to break G.U.N.'s training equipment when using it. All his abilities make him a capable opponent against many enemies, whether they are advanced fighter robots, beings with enhanced Mobian and alien abilities, or even entities with god-like powers.
Ares is equipped with remarkably strong armour that can withstand powerful laser blasts by elite fighter robots such as Apollo, and strong fast blows from powerful opponents such as Caput. Ares can also utilize a jet booster built into his back to help accelerate and fly long distances like Aliz, making him somewhat fast.
Ares can use radio waves to talk with other Nega robots and has sensors that allow him to detect energy signatures in various objects, areas, and beings. Some of his weapons seem to be specifically made for combat with Blaze, such as his arm cannon that was able to capture and launch Caput when he performed a tornado-dash, one of Blaze's signature moves. Ares is equipped with anti-virus systems to "purge" any malicious programmes and make sure he doesn't get infected. He also seems to be made to go across different terrains as well since he was able to get around the snow laden mountains with ease.
Like many of Eggman Nega's other robots, Ares was programmed with a limited personality, but thanks to Apollo's upload, it expanded a considerable amount and gave him free will. At first, Ares was only a rather rebellious character, immediately refusing his first mission from Nega out of anger as he believed it to be beneath him as he was made to destroy Eggman Nega's greatest foe, not a defective robot. He, like many other of Nega's robots, also seemed to fear his creator when he threatened to shut him back down for a decade after not wanting to carry out his first orders. His trait of rebellion later developed immensely thanks to Apollo, where Ares all out betrayed Eggman Nega and went to work for G.U.N. to fight the Nega Nation as part of Team Shade and get his revenge, ending his fear of his creator.
Ares is somewhat arrogant and prideful, making him think other Nega robots (especially older models) and his enemies are inferior to him, that he is the most powerful and will jump at any chance to prove so (usually through battle with another), no matter how powerful that being is. Currently, Ares' only goals in life are to take revenge on Eggman Nega for disabling him and carry on Apollo's mission. His pride of being a destructive war machine is a major part of him, and even threatened to turn Caput into "linked sausage" if he told anybody at G.U.N. he showed himself to be weaker than usual by building a grave marker and "whining" about not knowing his purpose in life.
Despite the fact that Ares has received the more peaceful Apollo's programming, Ares still likes to use destructive methods, battle with powerful opponents (even if they're his allies), and purge things with "fire" no matter what the situation is, (as long as it doesn't involve destroying life, as the very thought of it makes him "uneasy"). Stereotypical of most robots, Ares occasionally uses somewhat lengthy words, but most of the time uses casual human speech.
In respect to Ares’ relationships, he has few, but the most significant was with Apollo, whom he showed respect for even before his greater personality came to be. His relationship with Eggman Nega is one of revenge for never using him to destroy Blaze the Cat. At first, Ares' relationship with Caput was that of an enemy, but after gaining his new personality and emotions, Ares and Caput appear to be on more peaceful grounds and may even be on its way toward friendship, although they do appear to have a small rivalry between each other which they express while training their fighting skills with each other. His relationship with Alizarin seems to be on friendly terms as Aliz has actually felt free to be angry with Ares and call him things like "pyro" without fear, and Ares even seemed a touch embarrassed when she complimented him on how he had taken on Feist after they had retrieved the Sol Emerald.
Although Ares is a robot and has shown no romantic feelings towards anyone, he did show a touch of embarrassment when Aliz complimented him on doing a job well done with attacking Feist, possibly meaning he feels somewhat attracted to her.