On the face of it, Game of Thrones may appear to just be about sex, swords and dragons (as if that wasn't enough), but it's so much more than that. For at its heart, Game of Thrones is about people. It's a complex, layered character study into the things people do for love, the things they do for family and, of course, the things they do for power – power that, in Westeros, corrodes, corrupts and consumes. No one is conventionally good or evil, and nobody is what they seem.

Season two, premiering tonight on Sky Atlantic, goes even further. Adapted from A Clash of Kings (the second book in the series), it not only expands in terms of scope and scale but also introduces a range of new characters with their own background and narrative. It's daunting enough in the book, but with so many characters to cover already, the TV show has its work cut out so as not to make it confusing for those who've come fresh to the show. It's something that, judging from the first four episodes we've seen, it does well - but context does suffer. So, keeping that in mind, here's a spoiler-free guide to the new players in the most dangerous game of all. Who will win, and who will die?

Stannis Baratheon (Stephen Dillane)

Alluded to in season one but never actually seen, Stannis Baratheon is the eldest brother of former king Robert Baratheon – which means, what with Joffrey not actually being Robert's son, his claim to the Iron Throne is the strongest. Currently residing in Dragonstone (an island given to Stannis by his brother when he came to the throne), he's known as stubborn, humourless and possesses a harsh, unyielding sense of justice; all of which doesn't really set him up as a king anyone wants, even if he is entitled to rule. And then there's his involvement with a certain priestess...

Melisandre (Carice van Houten)

Two themes that are explored further in season two are religion and sorcery – Melisandre encapsulates both. Mysterious and powerful, she serves as a priestess for a god called R'hllor (a religion relatively unknown in Westeros, and to viewers) and as an advisor to Stannis. Her worship involves the idolisation of flames and light – the former said to give her visions into the future, something Stannis becomes reliant on in his quest for power. Her involvement with Stannis seems based on her belief that he's some sort of prophetic hero, Azor Ahai, reborn – one destined to defeat the great enemy of her god with a flaming sword. Keeping up? Good.

Davos Seaworth (Liam Cunningham)

All of the new characters in season two are cast well, but Liam Cunningham's Davos is ripped from the pages of the book so perfectly that it's little wonder he doesn't bleed ink. A low-born smuggler risen up as a knight by Stannis, Davos is fiercely devoted to the man who gave him and his family a future - even if he did cut off the first joints of his left hand. The rationale being that even though Davos saved Stannis's life by smuggling in food (including onions, which is why you will hear him being sneeringly referred to as the “onion knight”) at a past siege, the good didn't atone for his criminal past. Such is the harsh justice of Stannis - something Davos admires. He now wears the bones of the amputated joints in a pouch around his neck for good luck. As you do. 

Renly Baratheon (Gethin Anthony)

While hardly new, Renly plays a far more significant role in the second series than the first. Being the youngest of the Baratheon brothers, his claim to the Iron Throne is weak but thanks to his natural sense of charisma (something Stannis lacks) and the backing of the powerful Tyrell family, he's a contender. Merely hinted at in the books, Renly's sexuality (and his relationship with Loras Tyrell) is explored further in the second season – more specifically, how it affects his betrothal to Margaery Tyrell (which is giving him his military strength) and his reluctance to get her pregnant.

Brienne (Gwendoline Christie)

Gender politics runs fluidly through the arteries of George RR Martin's series – with one of its biggest selling points being that, despite being set in a patriarchal society against a backdrop of “whores” and arranged marriage, it's full of strong female characters (especially for the fantasy genre) fighting against it. Brienne, a fan favourite, is perhaps the strongest – literally. Loyal, honourable and immensely skilled in combat, she's played by Gwendoline Christie, who – despite being feminine in reality – pulls off her masculinity and ugliness with impressive ease. She holds a naively idealised notion of knighthood, despite the fact that most knights (and men in general) mock her looks cruelly with the name "Brienne the Beauty". It's this trait of idealism that is the most interesting thing about Brienne, as she tries to be a decent knight in an indecent time.

And there ends our guide. There are, of course, plenty of others we could mention - who is "the king beyond the wall", Mance Ryder? What is up with the mysterious Jaqen H'ghar? And just who in the Seven Hells is Theon Greyjoy? - but there is no time. Winter is coming. War is coming. Season two of Game of Thrones is coming.

Game of Thrones is on Mondays at 9pm on Sky Atlantic