Hodor is far larger than everyone else in the series, barring the Mountain himself, and it was even suggested by Osha that he could be descended from giants. As for his ancestry, fans have suggested a possibility that he is a descendent of Ser Duncan the Tall, who has featured in a series of short stories by George R.R. Martin, who had also said that a descendent of his would be revealed in A Feast for Crows. However this was almost certainly a reference to Brienne after she mentioned a shield with his crest on it in the armouries of Tarth. The other and far more likely suggestion is that he is actually a member of House Frey, as Nan revealed that Hodor isnt his name its actually Walder, and the only other character in the series to hold that name is Walder Frey. It is also said that many Freys name their sons Walder in order to curry favour with their liege and with the Brotherhood Without Banners hunting the Frey family in revenge for the Red Wedding, it could be that Hodor could end up being the last surviving male heir. Lord Hodor perhaps? The final Hodor related theory is based on the idea that George R.R. Martin uses Norse mythology throughout A Song of Ice and Fire and so the character is actually related to Höðr (also spelt as Hodur or Hoder). This may be the name of the god of the White Walkers, one that Melisandre has said must not be named. With Hodor now north of the wall and potentially heading deep into their territory, perhaps he is destined to resolve something related to their god.
