Metal Slade (Better known as Metallica) is a robot who was built by Circus Kane to originally be used as a killing machine. His body was modeled after that of a holodroid but was able to take the form of a metallic version fo Slade . Metal Slade obeyed every order Kane gave him like a mindless drone but was by far his best creation. Kane would grant Metal Slade a little bit more freedom, the freedom of thought. This got Metal Slade thinking about free will and being able to do as you please. He became quite saddened by the fact that he's a mindless robot while others did as they wished.
Soon, after months of being under Kane's control, Metal Slade met Blue Team, getting in a brief chat with Agent Tex who explained a little more about the concept of free will. The team was quite kind to him and this spurred Metal Slade to override his programming and leave his creator.
Now that he was able to do what he wanted, Metal Slade was welcomed to become part of Blue Team, even begin renamed in the process; Metallica, named after the band itself. Metallica became a helpful member in the canyon to both Red and Blue alike. He assisted Grif in getting out of a day of work, helped Simmons fix the warthog, go to Donut's tea parties (don't ask why), gave Tucker a few pointers on picking up chicks, gave Caboose a teddy bear, kept Church sane through a lot of what goes (even though he was doing fine before Metallica even arrived but hey, insurance), and became a friend with Tex without being ripped to shreds. He's practically done something for almost all of them and likes them with the exception of Sarge who he sees as a prick.
Later, Circus traced Metallica back to the canyon, looking to regain his robot and found Metallica arguing with Donut since Donut found out that Metallica had a tiny crush on Tex. The fight got physical and ended with Donut blowing Metallica's head off with a plasma grenade. Donut received a vicious ass whooping by Tex as a result while Church took his body back to base. Kane confronted the Blue to hand Metallica over but Tex, who had finished with Donut, disposed of Kane as well and Metallica was soon repaired.
Sometime later during his days with Blue Team, Metallica was wandering around until he encountered the Meta writhing at the bottom of a ditch. Due to his lack of knowledge of Meta's actions, he assisted him in crawling out of the ditch, much to the team's dismay but were willing to give him a chance as he was their friend. Things went smoothly for a while until Roadkill came in and stirred up confusion as Meta wore a Roadkill mask, making him come under suspect as the masked wrestler. Metallica came under some heat by his team as they knew Roadkill's violent reputation along with Meta and assumed Meta to be Roadkill.
Metallica, became depressed and sat in a juknyard until Donut came in (after aplogizing about the grenade incident) and spurred him into getting up and facing Roadkill. The robot would face Roadkill but the fight would not last long as he ended up being hurled down a cliff and almost dying in the process until Donut salvaged his remains and took him back to Blue Base where he was repaired. The next day, Metallica was placed under arrest due to Sarge filing him in for causing Meta to be loose once again. After a few choice warnings by Tex, Sarge dropped the charge and Metallica was set free, the team welcoming him back as they viewed him as one of their own and have grown on him and showing appreciation for him risking his own life just to earn back their trust.
Weeks passed and Metallica decided to join the military. He managed to get past the gruesome training and was put on the field. Metallica did quite well in the battle and quickly rose through the ranks to the put where he was made Colonel and leader of the FWM's Black Ops unit, even gaining new power armor to signify his position. This type of work required him to answer any call when needed which does keep him away from the Blue Base quite often but he's happy to do his part for the Multiverse.
Metallica was a very skilled leader, leading his troops on the frontlines personally and turning the tide of battle in the FWM's favor in a fair amount of time. One of his most well known campaigns was the Manhattan campaign where an army of Sectoids led by a few Muton commanders invaded Manhattan New York. Metallica lead a division of troops into the battle, and within a few days retook the city and restored it to its former state.
This however came to an end when Metallica heard of Equestria being invaded by North Korea and Apokolips allies with Ponyville being the last line of defense. The FWM couldn't intervene, fearing retaliation from Russia and China who threatened to ally with NK and Apokolips should anyone get involved. Metallica went to council, trying to get them to at least send Ponyville some troops to assist but the council refused to do so.Enraged by this ruling, Metallica gather a division of 2,000 men and was about to set out to Ponyville until a higher ranking officer attempted to stop him, threatening to arrest him if he continued to go through with this. Metallica paid no heed and the general ordered Metallica's men to place the Colonel under arrest but the troops retained their loyalty to their Colonel, risking they be court marshalled as well, knowing they fought for a greater cause. Metallica and his troops soon met with Nick Terakidan and the two allied with one another to protect Ponyville. With the well-needed reinforcements battling in the rear, the defending ponies managed to use the homefield advantage agains the Koreans and Apokolips forces. Russian and Chinese forces soon joined in, after hearing of Metallica's assistance but were quickly pushed back by the defenders as well but in the process, Metallica lost over half of his unit. After the battle, Metallica was demoted back to Private for disobeying orders and was court marshalled along with his men. Metallica reasoned that had he and his men not interferred the Koreans and Apokolips forces would've had a firm command post and possibly invaded the FWM, leading to more than just pony casualties and the annihilation of over half a company of men. The charges were soon dropped without any executions and Metallica and his men were free to go but was kept demoted, saying he can only reach Sergeant and no higher rank. Metallica was then ordered to turn his old armor in for a Venator variant. Though it wasn't as heavily armored as his previous power suit was, it was still quite thick and got the job done.
After being demoted, Metallica was sent on a mission with Havoc and a SpecOps squad of Commandos along with Riot Bots to destroy a group of Riot Bots who went rogue, turning against the Multiverse. The revolt was led by Zinc, a Riot Bot who lead a precinct that followed him in the revolt. Metallica and the SpecOps team dropped down at the precinct which was nearby a warehouse and factory. The Riot Bots and Metallica engaged the rogues in a lengthy battle, going through several rooms and corridors facing off against rogue Riot Bots with minimal casualties for Havoc's squad. Havoc and his men opted to stay and hold off the rogues as Metallica went after Zinc, killing any rogues who guarded him. Zinc attempted to convince Metallica to join him in the revolt but he refused, saying he would never betray his friends or the FWM in a revolt that leads to chaos and anarchy. The two fought and after a lengthy confrontation, Metallica killed Zinc by decapitating him with an energy sword. With their leader now dead, the remaining rogues were confused and scattered, only to be wiped out by Metallica who then regrouped with the Riot Bots before leaving the premesis. Sometime after the team's departure, an unknown, living rust parasite infected the offline rogue's bodies and turned them into undead robots. The undead precinct of rogues then left the area and headed to a junkyard where unknown events are taking place for reasons currently a mystery.
After disposing of the insurrection, Metallica began to wonder if the council was really conspiring with the Koreans and Apokolips when they refused to offer help to Ponyville. He explaine his reasoning to his company and the troops would rally behind him with one order; arrest the council for treason against the FWM. Metallica was reappointed as the Colonel of the troops as he marched into the capital with his men and without resistance arrested the council members. The majority of the council were found guilty of treason while some were innocent as they had opted to help Ponvyille. Metallica was then promoted back to Colonel where he rightfully belonged.
Metallica would later be deployed on Mars to halt a Martian invasion force from mounting an assault on Venus. It is there, he met with the first ever female Riot Bot named Aegis. The two grew a close bond and were very skilled in fighting side by side. Aegis was shown to admire Metallica's leadership skills but tension grew among their ranks as a fellow Riot Bot named Zix, who was known for being vicious on the battlefield. One day, Metallica, along with Zix's, company were led into an ambush by some civilians who were threatened into springing said trap. The attack was repelled but the Riot Bots suffered heavy casualties. Metallica was upset but was able to show some understanding to the citizens; Zix, however, did not take this lightly. Zix became infuriated that he was led into a trap and shot the chief of the village in anger, ordering the rest of his men to open fire. The defective Riot Bot was detained, along with those who obeyed his orders to fire upon unarmed civilians and were to await deactivation. Weeks after the innocent, Mars' aggressors eventually surrendered. Once the Mars campaign had ended, Metallica grew feelings for Aegis and confessed to her; as it turned out, Aegis felt the same way and the two began dating. The Riot Bot colonel married Aegis about six months later and had a huge reception afterward.
A few more months later, Metallica announced his retirement and left the armed forces to pursue a personal life. He continued his marriage with Aegis and hung out with the Blood Gulch gang and his former soldier colleagues. Metallica soon stumbled upon a young robot in the scrap yard and decided to take him in as his own, adopting him in the process. He named his adopted child Crank and began to raise a family. Things took a turn for the worst, however, when a full scale invasion of the FWM was launched by an individual known as The Master who possessed an army of 20,000,000 Helghast soldiers, packing Black Lantern rings. Metallica was unsure of whether he should join the fighting or not, wanting to make sure Crank was kept safe and that he would need to be there for him but he felt like he would be stabbing the FWM in the back if he refused to assist in the war effort. Church came in, after having gotten a call by the United Nations, to convince Metallica in joining the war and was successful.
Metallica is a bit of a joker around his friends at Blood Gulch and knows when to have fun. He cares about the Blues as if they were close family and views the Reds as friends too (except Sarge). On the battlefield, he's more calm, collective, and relaxed. He expected great discipline out of his men and was a strong-willed soldier, willing to give his life for the FWM. After his demotion however, Metallica became a bit less optimistic and more serious as he was still angry with the council for opting to let several ponies die and show that they're afraid of Russia and China joining the enemy forces. He secretly had feelings for Tex but has since moved on and supports her relationship, and we're using that term VERY loosely, with Church. Metallica is very protective about his friends and family, willing to put his life on the line for them and make hard decisions that others aren't able to execute. After marrying Aegis, Metallica's optimism grew and he became more mature in regards to Crank. He's particuarly sensitive when it comes to his sob as he does not wish for him to see some of the brutalities of war that he's encountered.