The Island - What the Heck is the Island?
The island of Lost is a very special place. What makes it so special? The electromagnetic light at its heart. The island is not the only special place; there are other electromagnetic pockets all over the world (as evidenced by the man Bernard took Rose to, Isaac of Uluru). Now, whether or not these other special places can be moved or spawn smoke monsters, I don't know.
We focus on the island, however, because that is where our story takes place. Thousands of years ago, an ancient person or persons discovered some of the special qualities of the island. They determined that the island was special and also that the light could go out. Other people came (or may have already been there) and became greedy, wanting the light and electromagnetism for themselves. The person or persons became the protector of the island, specifically the electromagnetism and the light. Because of the special properties of the island and/or the light, these people did not age and protected the light for many years. But one cannot protect it forever because after many years, they get tired and bored and wish to move on (through death).
The protector of the island is the one who makes the rules for the rest of the island. They are a kind of God over the island. Other people come to the island through various methods. They might accidentally stumble upon the island, or the God might have brought them there. My sense is that the protector/God (who doesn't age) cannot have children.
The woman we know as "Mother" could have been a replacement, or may even have been the original protector. It's most likely that she took over for her mother, who may not have been her biological, but adopted mother.
Mother either brought or took advantage of the fact the Claudia's ship sank near the island and pregnant Claudia washed ashore. Mother took this as an opportunity to train/mold a replacement. What Mother didn't know was that Claudia was carrying twins.
Mother raised the twins as her own. Jacob was inherently "good." He couldn't tell a lie and was basically kind. Man in Black was not "bad," but had more human characteristics, which lent him more easily to lie, manipulate, and be more selfish than Jacob. Circumstances enhanced these innate aspects of Man in Black's nature.
There was some intervention by a higher power, perhaps the island itself, that succeeded in highlighting the goodness of Jacob and turned Man in Black evil. When Man in Black saw his real mother (whom was dead and whom Jacob couldn't see), he learned the truth about Mother and his own people who'd been living on the other side of the island, unbeknown to Jacob and Man in Black, for the entire thirteen years of their lives. Man in Black turned his back on Mother and went to live with his people. Jacob, still seeing the good in everyone, often visited his brother.
Jacob's big weakness was that he saw that Mother loved Man in Black more and favored him, and was deeply saddened when he left. When Man in Black's hate became so strong that Mother knew he would kill her, she passed on the role of protector to Jacob. Jacob didn't want the role, because he knew he was the second choice, but Mother forced him against his will.
Man in Black was able to kill the protector of the island (Mother) because he had a special dagger (not sure if this was the first time it was used or if it had come from somewhere else) and stabbed Mother before she talked. If she would have talked, she could have persuaded him not to kill her. Mother knew he was coming and chose not to talk. She was ready to move on.
When Man in Black found out that Mother had taken Jacob to the special light (which Man in Black had been looking for ever since Mother had first showed them when they were teenagers and which he'd coveted), Man in Black fell into a jealous rage, which ultimately led to him becoming so evil that he became a pillar of black smoke. He could, however, take on the form of a human body provided that body was on the island (and not buried).
As the protector, Jacob changed the rules. One of the rules he couldn't change from before was that he and his brother could not kill each other. But he did change other rules. He knew how badly Man in Black wanted to kill him and knew that he would eventually find a way (a loophole), so Jacob began looking for a replacement.
Jacob's main rule was that taking over as his replacement would be the person's choice. He would not force the position on someone the way Mother had forced it onto him. He also wanted to prove to Man in Black that people could be good. Man in Black believed, like mother, that people were bad. "They come, they fight, they destroy, they corrupt."
For thousands of years, Jacob brought people to the island. He would not tell them what to do, but would wait for them to prove to Man in Black that people were good. Ships, planes, and air balloons were drawn to the island via Jacob, to bring people for Jacob and Man in Black to watch, both wanting to prove the other wrong.
Continue to the next page to read about Richard, the Losties, and flashes - backs, forwards, and sideways.