Renly Baratheon
The youngest Baratheon brother, Lord of Storm's End: charming, handsome, and beloved at court, with the easy warmth neither of his brothers could manage.
A soul of House Baratheon, born at Storm's End.
The fuller tale
Season One
The youngest of Robert's brothers, better looking than either of his siblings and better liked at court for it, with Loras Tyrell for a companion that everyone pretends not to notice is more than that. He tells Ned, while Robert lies dying upstairs, that the throne is there for whichever of them moves first and has the gold cloaks behind him — arrest Cersei, take the boy hostage, settle it before anyone else even knows Robert is gone. Ned refuses on principle, and Renly, unwilling to wait around for that principle to get him killed too, rides for Storm's End that same night, leaving the capital to Cersei and Stannis's unspoken quarrel over what's left of it.
Season Two
King of his own invention, with a hundred thousand Tyrell swords behind the claim and Loras still very much beside him in more than just the war council. Catelyn Stark comes to his camp asking for an alliance and leaves unimpressed; Brienne of Tarth beats Loras in single combat at a tournament and asks for nothing but a place in his guard, and gets it. He rides to parley with Stannis at Storm's End certain his numbers make him untouchable, and that same night, in his own tent, a shadow with Stannis's face and none of his solidity opens his throat while Brienne watches and cannot stop it.
How it ends for them
On the screen. Killed by a shadow (S2·E5)
He crowned himself with a hundred thousand swords at his back, and none of them could guard him from what Melisandre birthed in the cave beneath Storm's End. A shadow with Stannis's face put a blade through his heart in his own tent.
On the page. A shadow with his brother's face (ACOK, ch. 34)
In his pavilion at Storm's End, in front of Catelyn Stark and Brienne, a shadow with no body and his brother's face put a sword through the king in his rainbow armor. His hundred thousand swords went to other masters by morning.
Both tellings kill him the same impossible way, in front of the same two witnesses. On the eve of battle against Stannis — dawn in the books, with Renly armored and joking about his brother's punctuality; night in the show's tent — a shadow crawled into the light of the candles wearing something like Stannis's face, and put a blade through the king from behind his own guarded perimeter. It was Melisandre's working, birthed beneath Storm's End and fed on king's blood, and it made Catelyn Stark and Brienne of Tarth the only living witnesses to a murder no court in Westeros had language for. Brienne was blamed, and has spent the story since outrunning and outliving the accusation. His army went to other masters within days — the Tyrell strength to the Lannisters by marriage, the storm lords to the brother whose shadow killed him — which is as concise a summary of the War of the Five Kings as the tale offers.
Their chapters, book by book
A Game of Thrones 1 chapter that name them
A Clash of Kings 4 chapters that name them
Where the page and the screen part
The show makes explicit what the books imply: Renly and Loras as lovers, Margaery as a knowing partner in the arrangement, and Renly's discomfort with violence — the show's Renly is queasy at blood, where the books' version rides to melees happily enough and simply prefers politics to practice yards. The books give his kingship more texture: the Rainbow Guard (a Kingsguard of seven colors, with Brienne winning the blue at Bitterbridge), the peach at the parley, and a sharper strategic mind — his plan of starving King's Landing while his brothers' factions bled each other was working. The show trims his war to a few tents; the books make clear how close the realm came to King Renly, First of His Name.
Their journey
Where the two tellings send them to the same place the road runs whole; where they part, the screen keeps the left and the books the right.