Insurgent

The factions serve as meaningful symbols of the positive and negative characteristics that exist within all people. In the novel, the factions’ structure allows Roth to display the full range of human behavior in both its positive and negative manifestations. 

For example, the Abnegation are selfless, which proves to be their undoing, as they are unable to protect themselves from the Erudite-sponsored, Dauntless war machine. However, Tris ultimately finds that the selflessness she learned from her parents to be her greatest gift and strength. Likewise, Erudite knowledge brings scientific and technological advancement, such as medical treatments and more efficient agricultural techniques. It also brings the horror of mind-control serums. 

Each faction carries within it great gifts that each can use to uplift humanity or allow humanity to be destroyed.

The serums appear both as technological wonders and horrors. In their most positive form, serums are used for healing and pain-relief. 

However, the serums more commonly appear as mind-control technology. For example, in its most benign form, the Amity use a peace serum to keep their population calm. However, Johanna allows the serum to be cooked into the bread that everyone eats, which is a subtle, but manipulative, form of mind control. The goal is peace, but such peace is false; enforced by drugging the population into submission.