Hm... According to your profile you're playing a villain. Let's see: some we have some kind of cyborg who wants to bring order to humanity. Evil is usually associated with egocentric behaviour, or being a fanatic goody two-shoes, who crosses the line and commits evil things in order to do "good".
First think of what type of villain you want to play, does your toon has a misplaced feeling of being goodness, or being selfish and lusting for power?
Being a roleplayer which also plays Dungeons & Dragons, I have to deal with "alignments", which describes one's morality and ethics, here's what the manual has to say about it:
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ALIGNMENT
A character's or creature's general moral and personal attitudes are represented by its alignment: lawful good, neutral good, chaotic good, lawful neutral, neutral, chaotic neutral, lawful evil, neutral evil, and chaotic evil.
Good vs. Evil
Good characters and creatures protect innocent life. Evil characters and creatures debase or destroy innocent life, whether for fun or profit.
"Good" implies altruism, respect for life, and a concern for the dignity of sentient beings. Good characters make personal sacrifices to help others.
"Evil" implies hurting, oppressing, and killing others. Some evil creatures simply have no compassion for others and kill without qualms if doing so is convenient. Others actively pursue evil, killing for sport or out of duty to some evil deity or master.
People who are neutral with respect to good and evil have compunctions against killing the innocent but lack the commitment to make sacrifices to protect or help others. Neutral people are committed to others by personal relationships. A neutral person may sacrifice himself to protect his family or even his homeland, but he would not do so for strangers who are not related to him.
Animals and other creatures incapable of moral action are neutral rather than good or evil.
Law and Chaos
Lawful characters tell the truth, keep their word, respect authority, honor tradition, and judge those who fall short of their duties. Chaotic characters follow their consciences, resent being told what to do, favor new ideas over tradition, and do what they promise if they feel like it.
"Law" implies honor, trustworthiness, obedience to authority, and reliability. On the downside, lawfulness can include close-mindedness, reactionary adherence to tradition, and a lack of adaptability.
"Chaos" implies freedom, adaptability, and flexibility. On the downside, chaos can include recklessness, resentment toward legitimate authority, arbitrary actions, and irresponsibility.
People who are neutral with respect to law and chaos have a normal respect for authority and feel neither a compulsion to obey nor to rebel. They are honest, but can be tempted into lying or deceiving others.
Animals and other creatures incapable of moral action are neutral.
[/ QUOTE ]
(This text falls under the Open Gaming License and is free to reproduce. Link)
Your character is probably "Lawful Evil", which tend to be militaristic/tyrannical types. This might be a nice starting point.
Your toon, as you said, is a "soul/spirit" in a machine, so it used to live once. Who was the person who became the soul? Why did he willingly stopped living to merge with a robot? Did he tried the same things when he was a human?
Ask yourself questions, start with answering these for yourself and ask yourself more questions, maybe make questions out of those questions again!
To give you an idea how I work, I usually start with a one-line desciption, in the case of Baen Sidhe (read her background here): "Baen Sidhe is a Dhampir (=half-vampire, since I created her with vampire ears) with undead as henchmen" and with that idea in mind I played her. Altough I'm playing the game the thought of her background lingers somewhere in my head. Suddenly I questioned myself: "Hey, I'm playing City of Villains and I'm beating up other criminals, you can't see that as something evil! How can I make her more evil?" So I wanted to give her a wicked character trait. (Most notorious/evil people have certain oddities.) I made her necrophilic (thinking: it's a young adult and she has zombies with her all the time... why not?). From then on the idea came of the first zombie (Henri) being a former love intrest, but in an attempt to make Baen more wicked, the love intrest became the victim of a teenager with a lolita-complex who was killed after rejecting sleeping with her. Now I had a nice scene as part of her background, but a story is a collection of many scenes, so I started to think about the enviroment of that scene:
<ul type="square">[*]If Henri was a butler, to who? -> enter rich merchant dad, who happens to be a vampire, which was needed for the dhampir idea).[*]Could've he been married? -> Yes, enter his wife: reason for him to reject Baen one night (guilt) and an opportunity to kill it off (in order to underline Baen's evilness out of selfishness).[*] How did Baen discover her way to "remove" people standing in her way? -> Enter the bully.[/list]
As you can see asking yourself questions work well.
Back to that alignment thing, you can choose to use thinsg you read as references and use them (hopefully originally) for your characters. With the "lawful evil" idea, you could read up a bit on notorious dictators (try to avoid the most obvious ones!) and use that knowledge to create something yourself.
Things used for my character: I honestly know near nothing about New Orleans, so I use the New Orleans which is popular in horror-stories, the one described in stories by Anne Rice and Poppy Z. Brite, mixed with descriptions from roleplay-games like Vampire (even though I never played it), Ravenloft (from which the Dhampir template is loosely used).
Because I already decided to name her Baen Sidhe (original name for banshee, the ghost known to herald deaths in folklore), I wanted to stick to an Irish theme. But since the Rogue Islands are near the US according to the lore, I made her an Irish-American and instead of the obvious Boston area (where a lot of Irish-Americans are), I chose the (cliché) New Orleans for it's association with vampires in popular modern horror. Since I hardly know anything about Ireland, so I used popular Irish singers for her name (Sinéad Brennan, it's a mix of Sinéad O'Connor and the Brennan-family (of Clannad-fame and sister Enya). For her rebel teenage attitude I modeled her loosely on an ex-girlfriend of mine (Altough my screen-name is female (Baen Sidhe means something like "woman of the hills") I am in fact a male using RPG's to try to find out how people react to certain personalities who are unlike the real "me").
Last but not least, the above things only work when you can use your creativity. In my opinion two prerequisites for proper roleplaying are 1. basic social skills and 2. creativity.
You can blatantly copy a character, but that can bring you in a lot of trouble. As you saw in my examples related to my toon Baen Sidhe, I used quite some references and ideas to blend them into something new.
Try to keep your background basic, especially if you're not experienced with creating them. It's odd to have the entire life of you character planned, since roleplay relies heavily on improvisation it can happen that people ask things about your characters past which you haven't thought out yet. In those cases improvise something which doesn't break any lore you already had (unless you play a obsessive liar 
) and can be added afterwards into that background.
In short, use things you know to create your character (since this game is set on an altered version of "this" world you can use real history, which can be handy) and for the things you don't know: read up on it.
Good luck with it!
Edit: Holy Cow! Didn't expect it to be this long... Go to bed, Syr, go to bed... NOW!!!
wooo, long post lol, i just wanted to check, is this a plce for putting our characters back stories? or not? (might sound offensive certainly don't mean it) wouldn't mind giving Gauisus Somnium a nice story lol :P
I indeed made a tad long post. :|
I can become a wee bit enthusiastic sometimes. Necromantyr wants to have advice on how to create a good background story for his character. Maybe you can add input as well?
well, when i (finally) made the character i like i choose a lot of different things to add to a background story.
i suggest that you don't make too much up of it now, if you have a basic idea then when you go out to rp you can add to it in different ways depending on the situation, it is much they way i have done it. But as well as that, obviously you do need a substantial story about what happened before become a villain.
I also did my character in much the same way as B.S. i used things and people from my own experiences to make the character as it is, sometimes using books or even friends to make a character seem more realistic makes him easier to play.
Also your character needs faults/quirks he has picked up (for example my character tends to talk to a deity named Soloquial which appears to sit on his shoulder...) from whatever he has done so as to identify his character.
Then you need to know how he got in this mess in the first place, in your case, was the soul of anyone originally, is there something special about the robot he uses, does the soul have a master etc etc.
Just yet your imagination run wild, this is a character with a story, it can be almost anything you want, whatever appeals to you, you keep some bits hidden from the public, you show other bits off, you could be a Lawful or Chaotic good, whatever you think would be easiest for YOU to play.
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Well there is my contribute, i hope it helps, i tend to find stories fairly easy but that doesn't mean you should as well, i hope you get a nice one working out and look forward to meeting you at CT 
Well, I tend to start off a character with something I find cool. Take my favorite (and now sadly deceased) character, Red Saint; he started out (in my head) as a powersuit hero because I like those.
Then, as I RPed him, the character's psyche started to develop. It was, in fact, soon after the FA had been founded that Saint's personality suddenly clicked. That's usually the path all my characters follow, with the click coming after a few months. Wierd, hmm?
thankyou for the great advice it is much appreciated, well as for Necromatyr, the idea is loosely based on the Necrons from Warhammer 40,000 and the cybermen from doctor who, The character I would describe as B.S put it Lawful evil since his createst ambition is too end human suffering by converting them into Techno-Arcana therefore ending death and disease. He also willingly transcended (as I call it:P) because he was dying and feared death. as for the man before the machine I have no idea, as I said his motivation for transcending was he was dying but as to how he did it, nothing comes to mind. Though I have had the idea of using stolen Nazi technology combined with necromancy, but there is also another idea of using a Dark God called tetzogurion.
Hm... Nazi's did do a lot of research on mythicism and occultism (mostly in their cause to prove "aryan superiority") and there are many books/articles on that issue. It sounds like a nice idea, even though you have to find a good excuse as the technoogy resurfacing after over 60 years.
Good luck with your background!
as far as the technology resurfacing... you could say he was buried somewhere... in a tomb or something cause the nazis thought he was too destructive or dangerous and could backfire. Some archaeologists open it and badda bing badda boom, this could also give you a quest as such, (killing archaeologists ) where you need to get revenge on someone or somethingg... i am not sure it is your story, this is just an idea.
I have started this thread so people can post ideas and surgestions for backstories, SG story archs so on and so forth however I must admit I have my own selfish reasons.
Twice ive posted different versions of the Necromatyr backstory and twice Ive hated it! any surgestions?
the basic concept is simple A robot that houses a living soul, the motivation is to bring order to humanity by making more of its own kind, The Necromatyr are immortal since they can never die of age or sickness and if the body is destroyed they can simply choose to build a newone or go to the spirit world, Think a sci fi version of the undead.