- Walt got his specialness from his mother, or possibly a combination of his mother and father. Susan died from some weird blood thing (Ep: 1x14, Special) and that disease may have been what made Walt special. It seems if he was upset, he could make birds die. It might also be that he could make other animals appear, like when the polar bear tried to get him after he read Hurley's comic with the polar bear on it. Although, we know the polar bears were already on the island because of Dharma and that had nothing to do with Walt.
- Walt was special because his mother was Jacob’s wife on the island. Many years ago, long before the crash of 815, Walt’s grandfather – his mother’s father – was a physicist that was studying electromagnetism and its possibilities vis-à-vis time travel. His ideas were bold for the time (early 1970’s) and he was widely renowned as a crackpot. However, one of his good friends was Dr. Marvin Candle and he encouraged Walt’s grandfather to continue his work by joining the Dharma Initiative.
Sometime during that same period, Walt’s grandfather traveled to the island with his wife and his young daughter. When the family arrived to the island – the daughter, Susan (Walt’s mother), was about 5 years old. For the next few years she lived on the island with her dad, mom, and the other Dharma folks. On the day of the purge, however, she had gone for a walk on the island and had ended up off in the deep jungle in an area that she was not familiar with. It was there that she first met Richard. Because Richard knew about the purge, and about what was to happen that day, and because he couldn’t – in good faith – let this little girl be killed by the purge, he kidnapped her.
Susan was then raised by the Others for the next twenty years. At the age of 25, however, she wandered off into the jungle again. Discontent with the lifestyle of the Others, she desperately wanted to leave the island but found that there was no escape. While in the jungle she was so distraught that she attempted to hang herself; it was at that moment when she first met Jacob. Jacob took pity on her and he allowed her to live with him in the base of the statue. During her time with Jacob she became deeply knowledgeable of the island and learned about the “wheel” that allowed people to be transported off the island. But Jacob fell in love with her and she fell in love with Jacob. After some time she learned about Jacob and who he really was. Although pregnant with Jacob’s child, she felt betrayed by him so she escaped one day and found her way to the wheel. She then used the wheel to escape the island. When she returned to the real world, she made her way to NY and fell in love with another man – Michael.
Michael did not know that she was pregnant. But their romance was a whirlwind and within a month’s time they married. Soon after, the baby was born. After Walt entered the world, strange things began to happen. Meanwhile, back on the island Jacob was furious and ordered the Others to find her – no matter what – and bring her back to the island. He vowed also to use his special powers to make her return to the island – to more or less orchestrate her return to he island. But things happened very fast. She and Michael broke up, divorced, and she moved to Australia. When the Others and Jacob had finally located her, it was too late. She died two days later from a blood disease. But then Jacob and the Others learned of Walt and, more importantly, that Walt was Jacob's child. Thus, to get Walt back, Jacob made sure that Michael and Walt would be on Flight 815. Once Walt arrived on the island, it was the Others number one mission to get Walt. When they finally got him back, Ben betrayed Jacob and gave Walt back to Michael (at which time Michael left the island with Walt).
- Walt was Jacob’s first try at finding a failsafe, someone able to do what Desmond did in the finale, that is uncork the island. I think that’s the reason the Others were experimenting on him. Jacob wanted to find out if Walt was right for the job. The experiments probably didn’t pay out, his abilities weren’t the right ones, so Jacob chose Desmond for that role and he let Walt and his father go.