I love this show and I caught up on it last summer, but I have no clue how you guys keep up with character names. Maybe my brain is small. There's so much going on, i'm always like: "Oh man, i've seen that guy before. Why is her murdering Jon Snow?!"
It is a little easier when you've read the books (although that gets confusing because there are characters in the books who are not in the show and vice versa, and also some of the characters' names have been change from the book to the show). Also, maybe easier when you have time between episodes to kind of soak it it, rather than binging?
Also, that guy was Alliser Thorne (who really has never liked Jon Snow and is jealous of him becoming LC) or maybe you are talking about Ollie (the little kid whose parents were murdered by Wildlings and therefore he is mad at JS for allying with the Wildlings).