I CAN NOT BELIEVE IT!
When the show started,someone had a theory about Hodor actually being Rhaegar's son baby Aegon who was saved (instead of being killed by The Mountain and his people) and brought to Winterfell and the last words he heard from his mother Elia were "hold the door!" , that's why grown-up Hodor (alias Aegon) keeps repeating the word "Hodor".
I laughed so hard at this weird fan theory because it was somewhat absurd - but now D&D made it REAL. Hooray! I bow to you and your creativity! All hail fan fiction!