So, I'll explains Sam's situation..

He has been in a coma, in the forest, for this entire year. He survived by taking spirit out of the Life strings passively. Not enough to directly effect an individual, because he was taking a small amount from many strings, but enough to keep him alive. His kage warded his body and mind from decay during this time.

That is all I can tell you for now because Sammy boy has some inner plot to go through before you know the rest.

He has amnesia, however whenever he needs a specific memory, it returns to him. (will reveal why with time)

Back in the day he was an information broker who ran a vast information empire. He was one of the best. Mathias's personal friend and partner. (Sam doesn't feel the friendship connection emotionally anymore due to the amnesia) He is also schizophrenic, highly paranoid, and has the biggest ego since Charley Sheen. He has control issues, and does not deal with disrespect well. Basically me and Lost decided it believable for him to have researched into Ik, enough so that he has some very interesting information about him (none of which he remembers, except the one I mentioned).

Ik rose to power really fast, people wanted to know how, so Sam found out. Knowing things was good for business.

I am using this strategy for his past because it lets me uncover his life slowly, and sync it up with his changes as a character. It is one of the reasons I explained nothing about him in the prologue other than he likes tea and fine wine.