Sam's gone off to Maester U, and a lot of what he needs to learn will come from other people. Sam could meet other novices, including Leo Tyrell, one of the Tyrell cousins, whose character might be changed somewhat given how much of his family was just wiped out. In the books, Leo is nicknamed "Lazy Leo," acts like a spoiled brat, and is generally disliked by his fellow students. Alleras, who is nicknamed the Sphinx, is much more likable, if more mysterious, and could take an interest in Sam's arrival. (Alleras might also be a woman passing as a man, given the Citadel's gender-discrimination policies — the prevailing theory is that he/she is actually Sarella Sand, Oberyn's daughter.) One of the other novices who might greet Sam could be Pate, who starts off a little down on his luck and desperate for money. Without giving too much away, let's just say his desperation could turn him into someone dangerous. But perhaps the most crucial character Sam could meet at the Citadel is an against-the-grain maester named Marwyn, who is the equivalent of the cranky professor who drinks with his students during office hours and tells them the way the world really works. In this case, that involves the magical underpinnings of Westeros. Prepare to have your mind blown, Sam.