Suzanne Collins includes quite a few of these within the Hunger Games series, starting with the shapeshifter. One really never knows which side he or she will be on, so how can one rely on their status? Plutarch Heavensbee fits this description, because he is working under the control of President Snow as the Head Gamemaker for the Hunger Games... however, it seems that what he tells President Snow could both kill and help Katniss at the same time... which one would he be? (of course, we find that he is on the side of the Rebels).
There also two wildly different worlds, involving a clash between the two. This seems awfully fitting for the world of the Capitol (panem et circensis, or bread and circuses) and the Districts (frigida re vera, or cold reality). The whole conflict of the series seems to grow from the differences between the two worlds, as well as the class struggle caused by them.
Lastly, we have a dark night of the soul, where a decisive moment occurs that shapes the character's life thereafter. For Katniss, it is in Mockingjay, where she makes the decision to kill President Coin first, rather than President Snow. This was after realizing the animosity that she had shown her own rebels, as well as the strict dictator-y way of handling power and authority (seriously, she needs to loosen her corset and take a drink). She decides to stop what would seem to be a repeat of the tyranny that Panem faced under Snow's reign.