Basic Information
Past: We all know about Tom's past. Poor little orphan boy whom no one wanted. He doesn't much care for his father, obviously, and never really knew his mother. Shipped off to an orphanage at an early age, he learned much about life.
The caretakers were never too fond of him and were slightly afraid of his magical abilities. He was generally put to work, doing the chores around the place. He learned how to bake and how to do housework there. Nothing that grandiose but he can make divine cookies. Because of this, he has a sort of sweet tooth. He was thought to have telekinietic abilities by the Muggles who ran the place and was given both therapy and a lot of pills. Since his features were thin and he rarely ate, he was given more pills for nutrition and to make him hungrier. Since he was a rather moody little boy..you guessed it. more pills.
Big pills, little pills. White pills, yellow pills. Pills, pills, and nothing but pills.
You get the picture.
He has developed an annoyance towards Muggle medication, believing it to be the word of frauds and idiots.
He stayed a loner during much of his time in the orphanage. The other boys learned not to ridicule him early on, but he found their silence almost maddening. He wanted someone's attention but knew there was no way he could attain it save by trying to act like the Muggles and repress his natural tendencies.
For awhile, he tried this method. He killed his usual personality and tried being a part of the group. It ended in humiliation and Tom soon learned that it was better to be left alone.
He sought out companionship in the snakes around the the woods of the orphanage, developing his Parseltongue and learning how to use it best for his purposes.
Tom was no fool. He knew he was never going to be adopted, for he wasn't like the other 'normal' boys, so he looked beyond the day-to-day life of the orphanage and set about finding his own way in life. At the age of eleven, he left the small house and buggered off to Hogwarts.
He dominated the Slytherin House but knew to watch himself carefully. He made sure not to trip up on anything. It was in Hogwarts that he found his calling, first by the domination of the other kids, including those who were older than himself. He enjoyed his taste of power and soon crafted a new personality for himself. He used his past against others. The poor orphan boy. He could garner sympathy by the elders and he took control of the youngers.
Here he got the attention he had always craved for.
While he knew none of the other boys cared all that much for him, they did respect him and fear him, which was what he needed. All the same, there was no one there for him to talk to and he couldn't help but feel lonely. This loneliness preyed on his mind for quite a time before he deemed it to be a weakness and had to shut it away.
Many other emotions were shut away to him. The ability to care, remorse, sadness, and loss were only some of the few. He learned to live without them but still maintain the appearances of some of these feelings. He learned how to act and he learned that if he was not tied down with these petty emotions, he was given a much better view of the world.
He learned to read people, sharpening his own mind by constantly observing. He learned to manipulate and to better control. Having what appeared to be a natural talent in the Dark Arts, he learned how to master all that Hogwarts had to teach and, in the summer, taught himself quite a few other things. With a hobby at hand and a group of people he could control, he seemed to have everything he ever wanted.
Of course, we all know what happened with the chamber of secrets and the like, no need to go into detail about that.

He left Hogwarts, graduating with Honours, top of his class, etc, etc. He took a few odd jobs after which, preferring to travel from place to place. He would settle down in one area, get a job, get a flat, and learn all he could from libraries and people who were supposed experts in the Dark Arts. Throughout his travels, he changed quite a bit. The repression of emotions became Tom while Tom became something else, something darker than before.
He needed to seperate himself into two different halves, wear Tom as a mask while becoming what we now know of as Lord Voldemort. To do this, Tom had to work damned hard at repressing both himself and his Muggle side.
To him, Voldemort is a Pureblood. The prejudice he had dealt with at Hogwarts did not touch him. No one at the school had suspected his origins, thinking him as pure as the rest due to where he had been placed. He knew there were wizards and witches who did not feel that Muggles or Mudbloods should even exist and after living with the Muggles for as long as he did, he could not blame them.
To immerse himself completely in the Dark Arts, he felt he had to become a pure wizard, thus he had to change his own blood.
He literally did try bleeding himself out but was found, hospitalized, and released. Resolving himself that perhaps he should not be so damn literal, he tried another tactic. He would change himself.
To do this required transformations not of the skin, but of the soul. Blood is one's life and one's life is his essence. The soul is the source of this essence, and so in order to change himself, something had to be done from within.
The rituals he put himself through were harsh and brutal and ended him with several side effects. He had a penchant for blood and pain now, he had a strong sadistic side, and he found himself becoming less human.
Nevertheless, he felt he had succeeded. Tom was no longer and his name could only exist when he had to hide, for he now knew what he wanted to do with his life.
Enter the Dark Lord.
Voldemort arose, sprouting many rumours as to his existence. Some said he was based up of all the souls of wizards and witches that had been killed by Muggles. Some said he was just some crazy jerk-o who needed a life. Either way made Lord V roll his eyes and calmly bury his nose back into the book he was reading.
Yes, Voldie was still a loner. And he did not intend to stay one for very long. It was in this loneliness that he found his repressed memories arising. In order to keep himself from becoming depressed, he involved himself in the company of others, recruiting them one by one to follow wherever he chose to lead.
This involved a lot of time and a lot of hell.
He still can't forget that time in Spain when he and a few others where chased by a bunch of Muggles with torches and pitchforks.
Those people had no vision!
Enter a very annoyed Dark Lord.
After the debacle of Spain, Voldemort decided that perhaps he should lay low for awhile. He became Tom once again and started setting up a few bases all around Europe. He preyed upon the countries that weren't nourishing, that had a failed economy, that were looking for something different, anything to get them on his side. The people were looking for someone to blame and that's what Voldemort gave them. He provided them a scapegoat and someone to lead them on their merry way.
The Muggles and Mudbloods proved easy targets, but the so-called Cause wasn't what Voldemort was going for, it wasn't who he was and it sure as hell wasn't why he was doing what he was doing.
He recruited people who flocked to him, he came to a few people and recruited them. It mattered not, sooner or later, they all had a reason for being there. Some had personal reasons, others for the Cause, others for thrills, and yatta yatta yatta.
Somewhere during his travels, Voldemort had met up with a young woman. Or a young woman met up with him. He really can't recall since he had just come down from a particularly harsh ritual. The two met up, nevertheless, and a night of merriment was had by all.
No one counted on the woman getting pregnant.
How's that for a kick in the arse? Knock one woman up and you get branded for the rest of your life.
From the woman came Lily and that's a different story for a different bio.
And then he found the Malfoys. Befriending young Lucius, he became more of a father to the boy than the youg Malfoy's own father was. From Lucius, he moved on to bring about the Inner Circle. From the Inner Circle came the leaders of his armies, and from them came Severus Snape.
In all honesty, Voldemort should have realized that Snape was the weakest link in the chain, but he had been too busy falling into insanity. The demons that had plagued him throughout life grew out of control and from them came the breaking down of what was once a brilliant mind.
What happened next, everyone bloody knows. What they don't know is just why Voldemort went to the Potters that night when he knew what the end results could be. Rumour is that he knew of Harry's power and that the little brat was destined to become stronger than him. Misery does not like company in this case.
Or it could be just the last remaining humanity in Voldemort, trying to put an end to an unstable mind before more were killed and Lily or Harry was his one way out.
Either way. Moving on. We all know what happened in Books I, II, and IV. Voldemort has risen once again and now he is coming for the traitors, his enemies, and even his own followers.
He can deal with betrayals. He can deal with Potter. He can even deal with Lily. The only problem is that he can't deal with himself.
Some basic facts...
He despises his Muggle name. This goes without saying, really.
Kindness can touch him. He believes the world to be incapable of caring about anyone or anything, himself included. To feel cared about is a huge revelation to himself and makes him happy of all things. It is the one facet that can bring out his repressed emotions that he would allow.
He lives to control and to manipulate, obviously, and will stop at nothing to get his way. All the same, he wants to have a good time while doing it.
Every Death Eater is his favorite before he Marks them.
I am the one, Orgasmatron, the outstretched grasping hand
My image is of agony, my servants rape the land
Obsequious and arrogant, clandestine and vain
Two thousand years of misery, of torture in my name
Hypocrisy made paramount, paranoia the law
My name is called religion, sadistic, sacred whore.
I twist the truth, I rule the world, my crown is called deceit
I am the emperor of lies, you grovel at my feet
I rob you and I slaughter you, your downfall is my gain
And still you play the sycophant and revel in you pain
And all my promises are lies, all my love is hate
I am the politician, and I decide your fate
I march before a martyred world, an army for the fight
I speak of great heroic days, of victory and might
I hold a banner drenched in blood, I urge you to be brave
I lead you to your destiny, I lead you to your grave
Your bones will build my palaces, your eyes will stud my crown
For I am Mars, the god of war, and I will cut you down.