The world of HBO's Game of Thrones is confusing. Once you've read our recap of the most recent episode, you still might have some nagging questions. Who was that one guy again? And why did he have to kill that other guy? Googling to figure out the answer from the books is fraught with spoilers from later in the series. What's a Thrones watcher to do? Allow us to be your guide. Every week, we'll be here with backstory on the latest episode, providing context without getting ahead of the story. 

For this week's season premiere, there's a lot to tackle, from a vengeance-obsessed bisexual prince to creepy cannibal wildling people with lines on their faces. Who are these guys running the Night's Watch who don't like Jon Snow? And what was the point of giving all that attention to Tywin's fancy new sword?

Prince and the Revolution

Yes, Prince Oberyn Martell, the "Red Viper," is super cool. He is part of the Martell family, which controls the most southern of the seven kingdoms. Oberyn's basic purpose, as he explains to Tyrion, is to get revenge for his slain sister.

Here's the deal: Back when the Targaryens ruled in King's Landing, Oberyn's sister Elia Martell married Prince Rhaegar, who was the first son of the Mad King Aerys and next in line to the throne. The couple had two young children and raised them in King's Landing. The trouble for the Martells started when Rhaegar ditched Elia to kidnap and run off with Lyanna Stark, Ned Stark's sister. Robert Baratheon also loved Lyanna, so he and his allies started a huge civil war to get her back, "Robert's Rebellion." As the war progressed and the Targaryens started losing, Tywin Lannister jumped into the fray, and his forces sacked King's Landing, killing and raping and generally doing terrible war things, ultimately placing Robert on the Iron Throne and establishing the political climate as it existed when Game of Thrones began.

One of the people under Tywin's command was Gregor "The Mountain" Clegane. The Mountain is huge and is the Hound's brother, and you probably remember him as the guy who lost in a jousting tournament in season one and then decapitated his horse immediately thereafter. He's scary. During the sack of King's Landing, The Mountain found Princess Elia Martell and her two kids in their castle room and wreaked havoc. He and a small force killed one child, smashed the baby against the wall, and then — at least as the rumors go — raped and sliced Princess Elia in half. Tywin then wrapped the dead royal family in Lannister colors and presented them to the throne to prove that the Lannisters could be trusted to be anti-Targaryen.

So Prince Oberyn wants justice for his sister's rape and death, yes. He blames Tywin, the entire Lannister family, and specifically The Mountain for that crime. Even though the rape and killing of his sister was years before, the Red Viper is still out for revenge.

What's with Tywin melting down Ned Stark's old sword?

The episode opened with Tywin melting down the old Stark sword into two of his own, some tidy symbolism for the way the story has gone for both the Lannisters and the Starks thus far. The Stark greatsword "Ice" — yes, it had a name — was one of the few remaining swords made of Valyrian steel, which is a particularly sharp yet light metal that very few people can make anymore. The few Valyrian steel swords still in existence are heirlooms in famous hotshot families, and the Lannisters haven't had one since theirs was lost at sea years before. So not only does this symbolize the changing of the guard, it also bolsters the Lannister family's power and makes lower the Starks.

What's wilder than Wildlings?

So who were those scary bald cannibal dudes with Ygritte and Redbeard? Those are a tribe of wildlings called the Thenn. The main leader is named Styr, also known as the Magnar of Thenn, which is a fancy way of saying leader. All the Thenn people appear to be bald and have weird lines on their head for some reason, so it's easy to identify them. You can tell which one is Styr because he is the only one who has a speaking part. They are cannibals, I guess. (Neither the scarred appearances nor their cannibal practices are present in the books.) The Thenn have somehow made it south of the wall — they "took a detour" ¯\_(ツ)_/¯ — and are now joining forces with Ygritte, the red-bearded Tormund Giantsbane, and the other wildlings to attack the Night's Watch. 

The larger point that the scene is making is that Mance Rayder, King Beyond the Wall, united a bunch of disparate tribes who are typically enemies to join forces and attack the wall. The Thenn, free folk, giants, and everyone else generally fight and hate each other. But the oncoming ice zombie apocalypse has turned them all into allies of convenience.

Who are the current, sour-faced leaders of the Night's Watch?

The Night's Watch is now led by these three, from left to right: Janos Slynt, Alliser Thorne, and Maester Aemon. Slynt used to be the leader of the Gold Cloaks, the quasi-police force of King's Landing. He was the one who conspired with Littlefinger to betray our old pal Ned Stark. Once Tyrion became Hand of the King, he sent Slynt to the Wall because he couldn't be trusted. His face is very punchable.

Thorne, in the middle, was the master-at-arms of the Night's Watch, the guy who was mean to Jon, Sam, and the rest of the young recruits back in season one. He doesn't like Jon because he's jealous of his good looks, sword skills, and protected childhood.

Finally, on the right is Maester Aemon, the old blind voice of wisdom on the Night's Watch's board of directors. There was a minor joke in the most recent episode about how he can tell truths from lies because he grew up in King's Landing. A short explanation: he is Aemon Targaryen, one of the last remaining of the Targaryen family, and grew up at the royal court. But he chose instead to forsake his family name and join the Night's Watch, and he's been there for a long, long time.