Headcanon: Born to a relatively normal family in Paris, France in the 1930's, Spy had a relatively normal childhood; he played with the kids in his neighborhood, had a handful of friends, did well in school, etc, etc. His family was stable and he had no siblings.
One day, his father's business was starting to collapse, causing them to pack up and move to America in hopes of improving his chances of succeeding in his trade. The industry was just starting to flourish there, and so Spy's family did manage to get by, even in a foreign country.
Spy hated America. It was so sloppy and busy and dirty, and his contempt for the country didn't help him in school. He became an outcast; his classmates shunned him for his accent, for obviously being someone different. The feelings were mutual; Spy held a contempt for his peers that matched the intensity of their hatred.
Needless to say, Spy's attitude got him in quite a bit of trouble; he became a delinquent, spending his free time taking out his anger on his peers who wanted to pick a fight, or anyone who gave him the wrong look. He became well renowned for his skills with a knife and his quick reflexes, and soon enough, he was well known throughout the city as, "Le couteau", or "the knife".
At home, he was an entirely different person. He still loved his family very much and he didn't want them to worry about him. It was here that he maintained his studies, creating the image of a quiet school boy. When he was of age, though, he was extremely restless; he couldn't stand living in New York anymore, so he told his parents he would take his high school diploma and get an honest job. A lie, of course; he was planning on traveling and seeing where the rest of this filthy country would take him.
He was stopped somewhere in Ohio. One of his previous enemies had been following him his whole drive. They caught up with him and offered him a job as part of their group; it was an underground network of information, and they wanted to use Spy's intellect and his French background to spread internationally. He was offered good money and a chance to get out of America, and he took it in a heartbeat.
Spy spent several years as a Spy, going undercover in several different European countries. He was naturally sneaky and had a way with words, but that didn't mean that he was good from the get go; he had to be rescued a few times in his early years, and he hadn't escaped those times without scars. But he became good at his job; he built a persona that was nice and friendly, someone you could trust, someone entirely different from himself, and allowed people to think that he was open so that his targets would be open, as well.
Throughout the years he'd picked up many names and titles and faces, but one day someone addressed him by his real name. This someone was an agent from RED, and it turned out that they had been keeping tabs on him since he started his exploits in Europe. The agent offered Spy a job that had twice the pay of the original group he was working for. From the looks of it, RED was much different from his normal Spying career, but the information they had on him scared him, so he took the job with some reluctance.
At the age of 31, he was sent out onto the battlefields of RED and BLU, and he worked there for five years. In this time, he met the BLU Scout's mother. He hadn't known it at the time, but they met in the civilian town outside his base, where Spy had been picking up the weekly rations. She had just said goodbye to her son, and her sobbing caught Spy's attention. After the exchange, he was two hours late from returning to the base, but he had a new girlfriend on his arm whenever he was out in the civilian world.
Extra Details:
The Homosexual Incident:
There was a time where Spy was without a job/assignment. He was back in France, enjoying a cigarette and the atmosphere and the feeling of being at home, when he found someone who caught his eye. It was a waiter at a nearby cafe; younger than him by a handful of years, friendly, a bit clumsy, and courteous, from the looks of things. There was something about his eyes that reminded him of his mother. He immediately went to see the man, converse with him. This man became his next fling.
If he's honest? This man, Francis, grew on him quickly, and was a lot closer to him than anyone else he'd let into the bedroom. He was honest and funny and just got under Spy's skin and got real comfy. Sometimes, when Spy thinks about it, at that moment when he was with Francis, Spy thinks that maybe he could have quit spying to be with him.
But, seeing as it was the 50's, it wasn't happening. Spy had gotten really careless, especially since they were both young and foolish. An enemy of his saw him with Francis and immediately called a former and frequent employer of his. They plotted to kill Spy and his boytoy and rid the world of their unnatural behavior. Spy ended up with several bullets in him; the first one caught him by surprise, but the rest were taken so Francis could escape with his life.
Spy had to tend to his wounds on his own, and it took him a long time to recover. He even considered coming back home for a while to stay low.
Francis did find him again. They met one last time before Spy left for Brazil. Francis wasn't afraid to take him back and move somewhere else, but Spy refused: he would only bring danger to Francis again and again. Francis said he didn't care, but Spy did. Deep down, he was also afraid he had gotten too attached to Francis. He almost died; it was the only reason his assailants left him, they thought he had died.
Spy was left jaded about relationships because of this and swore only to keep relations with others shallow. He also refused to bed young French men ever again.
The Adjustment Incident:
Spy was used to being a low class, sneaky, dirty foreigner in America. When he returned to Europe, it took him a while to get over his ruthlessness. At first, he was kept to the assignments that only required killing. But soon enough, he was needed for intel collecting, so he was sent back into the public.
He picked up a few things from sneaking around, of course, but he blew a few of them out of proportion. He didn't know how to dress and ended up mixing a few things up, he didn't know how to speak properly, he didn't know how to act properly. He begged his employers to return him to his usual jobs, but Spy's profficiency with languages had his employers convinced he was made for higher things. They kept giving him similar assignments
/holy fuck how did this all get deleted, fuck.
in short: he was forced to learn how to adapt because people were chasing him otherwise.
In regards to changing his personality:
he kept getting caught despite changing get ups, so he observed people in bars in his downtime to understand people better.
The Delinquent Incident:
Back when he was still in America, Spy learned how to manipulate people to be used however he wanted to. He leanred how to blackmail people, he learned what people would do for the things they loved. He was a force to be reckoned with, people knew that, because of his ruthless behavior.
Eventually he had the police under his hand. That was how he avoided being found out by his parents. No one questioned him, and he was allowed to rough up whoever he wanted. He threatened them with their children's lives.
There was someone who got away, who almost told his parents what was going on. Of course, his parents were the only people who could stop him: they were the only one who could influence him/get to his head.
That person was Spy's first kill. It made everyone else take him a lot more seriously, and he was allowed to live the rest of his adolescence in power.
Personality:
Headcanon: While Spy can be all the above things, and that is truly what he thinks of his opponents and sometimes his own teammates, when on the job doing actual spying, Spy is can appear to be much nicer. He can be empathetic and open as a lure to his targets; after all, it's easier to trust someone who looks like they will reciprocate the trust given.
His default expression is dry and calm. He's a no-nonsense kind of guy when it comes to work (being undercover, sweet-talking people, etc). When you talk to him, he seems like a gentleman. Though he does have a tendency to slip in underhanded comments and insults, which can sometimes only be detected once his target thinks back on their conversation.
Spy is prim and proper. He is never seen without a suit, and he has a distaste for things unruly. Jarate, also known as piss in a jar, thrown at him by his enemy, the Sniper, disgusts him profusely. Growing up in dusty and dirty streets also caused him to build this distaste. It unnerves him to be in places that are dirty for too long.
Spy's greatest fear is to die as just some Spy from RED. He built a reputation in Europe before joining RED, but since he's been with the company, he had to cut several of his ties. This is also one of the reasons why he finds it more beneficial to be a nice Spy; his targets will remember him more easily that way, even if it is under a fake name and face. After all, every one of his facades are still a part of him.
Under all of his titles, names, and faces, Spy sometimes loses track of his real self. His real personality normally comes out when he's in a dire situation on the battlefield, where he swears and jeers and throws out childish taunts. That is the real him: the juvenile delinquent he became once coming to America. The young school boy he used to be is still there, too, but it's been suppressed for the longest time. The one person in the world who knows how loving he can be is the BLU Scout's mother. He treats her with love and respect, and despite their circumstances, he tries to be understanding when it comes to the BLU Scout. In any case, it's difficult to backstab a Scout anyway, so it's not as difficult as you may think.
The one thing Spy does to remind himself of his real self, what he used to be and how he got to become part of RED, is to look at his first knife. He's kept it since his school days as a way to anchor himself to the real world; the knife can cut, can hurt and remind him of his humanity.
Powers and Abilities:
Spy's spying skills are the only abilities he has. He can speak fluently in several different languages (French, Italian, Spanish, German, English) as it had been a necessity when he'd traveled all over the world to do his spying. He can talk his way out of most situations, as his business persona is a friendly one.
As a Spy, he's also very sneaky; he's not the biggest man, so he can slide through slim spaces and can slink around in the dark. Though his running abilities are average, he can be short of breath sometimes; years of smoking is bad for the lungs, after all. But otherwise he's physically fit and can do pretty well in a close combat fight. He also has good aim with a gun, and if given the enough time and patience, he can fire off headshots from a distance.
Anything else?: Spy has a French accent, though he's capable of losing it and even adopting different ones. He sticks to the French one because it reminds him of home.
Spy's Love Life (and other views on romance/sex/etc)
As a teenager, Spy was never really too good with women. He knew how to treat them right and was generally a gentleman when it came to handling them (something his parents drilled into his skull. they wanted grandchildren, what could they say?) but due to his reputation, they stayed away from him. It didn't really bother him; he knew why they stayed away from him, so he didn't try to pursue any. Besides, if they let his violent reputation prevent them from trying to get to know him, they weren't worth it.
He was too busy to deal with relationships when he got his gig collecting intel. None of his relationships, platonic and romantic, were real and he wasn't in any hurry to change that. He picked up women whenever it was convenient; maybe she had access to certain information, or had the keys to a certain building, or maybe she had a grudge against someone he needed to eliminate and was willing to do anything to help him. He never invested too much of himself in these relationships; he molded his persona to fit the woman's interests and took advantage of her in as many ways as possible.
When it comes to sexuality, Spy will tell you he's as straight as an arrow. It's mostly true in a romantic sense: he can only imagine himself in relationships with women. But, as stated above, he will take advantage of anyone he sees fit. On the rare occassion, it will be a man. These encounters are normally brief, and usually used for taking information rather than getting little benefits such as permission to enter certain establishments.
He appreciates both female and male bodies and does not mind taking the submissive or the dominant role. He adapts to whatever suits the situation best.
Sometimes, when he's really bored, Spy will mess around with a man or woman who has taken his interest. It may have been their intellect or their humor or their looks, but if Spy has the time, he will go in for the kill. He's usually successful, considering his ability to read people and change to fit their preferences, but if he's shot down, he usually leaves them alone. And he will never talk to them again. If it's an especially bad rejection, he'll avoid returning to the city they were in, and if need be he'll take on an entirely new personality just to avoid being approached.
When he met the BLU Scout's mother, it was one of the incidents where he was simply looking for a skirt to chase. As a new member of RED, he was already starting to get bored of his work's repetitive nature. But this woman was different. She seemed to be able to pick up on his tendency to change according to her wants and called him out on his bullshit. After that, Spy was ready to leave her alone, but that conversation kept getting to him. Finally, there was someone out there who was able to read past his masks, his disguises, maybe she was someone he could try to really connect with.
So he sought her out again and she let him in. It was a slow process; Spy was having difficulty preventing himself from trying to change, trying to be less sarcastic and more of a man that deserved such a sweet woman. But she would always beat him over the head for it, threatening to leave if he tried to pull that on her.