The protagonist is the narrator of The City and Its Uncertain Walls and experiences reality both in the real world and in the walled-in town. The protagonist undergoes an intense journey over the course of the novel, overcoming heartbreak from an early age and learning more about himself as he lives in two worlds. After the disappearance of his girlfriend, the protagonist is defined by his insecurity and isolation:

But is that possible? To reserve a secret part of your heart for someone, while another part of you loves someone else? To some extent, but it can’t go on forever. So I wound up hurting my girlfriend, and that ended up hurting me. And I became all the more isolated and alone (111).

When his girlfriend disappears, he waits for her, and even when he moves on and begins seeing other women, part of his heart stays behind for her. This causes him to be split, sharing some aspects of himself with others while reserving his deepest self for the vanished girlfriend, mirroring how he is eventually split between two different worlds. He cannot stand to be split like this and hurt himself and others, so he eventually distances himself from love, choosing to be isolated and safe from pain.