Cersei and Jaime

Isaac's wife Rebekah was barren, so Isaac prayed to God to give his wife children. Rebekah became pregnant with twins and God told her that two nations would be born from each, but the elder would be the younger's slave. The twins are born: Esau is first and Jacob is second, coming out holding Esau's heel. Esau is a hunter and an outdoorsy kind of guy while Jacob stays inside and weaves. One day, Esau comes upon Jacob making some soup, and when he asks for some Jacob says that Esau must give him his birthright in return for some soup. Well, it must have been some damn fine soup because Esau relinquished his divine birthright on the spot. Moral: never underestimate the power of soup.

The image of one twin holding the other's heel is fairly indicative of conflict to come, and while reading this story I was thinking of a set of noble twins in the Game of Thrones books that mess with these rolls in an interesting way. These characters are Cersei and Jaime Lannister, the latter of was holding the former's heel. I will try to explain this without giving away too many spoilers.

if(objections){
    stop reading
}
else{
    For the first few bit of the story it appears that the George RR Martin intentionally switches the to roles of the Lannister twins. Jaime, the younger, heel-holder of the pair, has no interest in the ridiculous amount of money, land, and power that was his birthright and instead chooses takes a position of knighthood that makes it impossible for him to claim it. Cersei, the older, is constantly frustrated by the fact that, as a woman, she can never truly claim the monarchy, and instead must use her son as a surrogate king in order to take power. This is the exact opposite of what happens in the biblical story in both individual roles and inheritance rights. However, events change when Jaime suffers an injury that prevents him from continuing his rugged lifestyle. He returns to the capital, crippled, and is forced to live quietly in his knightly quarters reading and slowly discovering all of his sister's nefarious plots and schemes. In this way, Jaime becomes more like his biblical counterpart, and when Cersei's plans begin to fall down on her head, Jaime begins to realize that she might not be such a great gal after all. The name Jaime is derived from the name Jacob which can mean 'he who supplants', so I think that it is not unreasonable to predict Jaime soon turing on his sister and even joining the growing rebellion against her. Of course, this is all assuming that Martin doesn't freaking die of old age before the next two books are finished. Knock on wood.
}

Cersei looking regal and slightly annoyed
[source]

Jaime looking confused but still in charge
[source] 

Tyrion Lannister: younger sibling to the twins. Doesn't fit into this discussion but he's easily the most entertaining character and the closest thing Game of Thrones has to a protagonist.
[source]