Caroline
The character Caroline, Augustus's prior girlfriend who died of a brain tumor that changed her personality and ability to control her emotions as her illness progressed, is formed entirely from a few conversations between Augustus and Hazel and what Hazel is able to read publicly on Facebook. Even with this limited information, Green creates a terrifying, enthralling, and tragic image of Caroline. Imagery of what cancer can do to a person is, obviously, rampant in The Fault in Our Stars, but Caroline's case is perhaps more gruesome than any of the other cases of cancer in the book because of its influence over her emotions, personality, and relationships. Even more than hurting people after you're gone, as Hazel fears, Caroline's case personifies the hurting of people before you go.
Amsterdam
Neither Hazel or Augustus have had the ability to travel much, as both were diagnosed with cancer in their early adolescence which saps away the ability to go far from one's doctors and much of the funds of a family. Now that they are able to take the trip, Hazel shows a first look at Amsterdam to the reader with amazing imagery. The night that Hazel and Augustus go to Oranjee, Hazel thinks and converses at length about the canals, pedestrians, petal "confetti" (p.163) in the air, the slow descent of the sun, the "bottled stars" (p.163) of champagne, and more, creating a rich and welcoming background for some of the difficult scenes at this turning point in the book.
The World of "Cancer Kids"
Green introduces Hazel's world to the reader through a trip to Support Group. She explains the nuances of competition for health, displays of health level through using the stairs or elevator, the process of interacting with a "support group" one does not feel particularly connected to, and even minutia such as what kind of cheap snacks and drinks are provided. Throughout the book, Hazel's story allows a deep immersion into the world of youths with cancer, from the ecstatic moments of finding other people who understand your pain and frustration to the soul-sucking boredom of lying in an ICU bed waiting to be healthy enough to go home.
Water and Drowning
From the dark fluid draining from Hazel's chest to a bag to a dream in which she is "alone and boatless in a huge lake" (p.301) to the T. S. Eliot poem that reads “We have lingered in the chambers of the sea / By sea-girls wreathed with seaweed red and brown / Till human voices wake us, and we drown” (p.164). Even Green's epigraph, a quotation from An Imperial Affliction and therefor written by Green himself, takes place at the ocean and compares water and time. Hazel once almost died by drowning within herself, and rather than a drowning at sea this fluid also deoxygenates her blood and causes incredible pain. The imagery of water throughout the story parallels Hazel's fear of drowning due to her body's condition, even when water is depicted in beautiful, calming circumstances like in the canals of Amsterdam.
