Leading up to World War II, the Fascist Party centered the nuclear family and its importance to Italy—but family, in all its forms, serves as both bulwark against and perpetuates trauma throughout Eternal. Friends Elisabetta, Marco, and Sandro create their own version of family that both highlights their own families’ failings while compensating for these failings. Trauma can be passed on through families, both birth and chosen, but so can resilience. Familial bonds change throughout the novel to accommodate the changing circumstances of the war.

Both Marco and Sandro’s parents struggle to accept Elisabetta as a potential daughter-in-law. To the Terrizzis, Elisabetta will always remind them of the affair between her mother and Marco’s father. To the Simones, her relationship with Sandro represents a dilution of Jewish identity and legacy. Massimo and Gemma are wary of historical antisemitism and encourage Sandro to take a Jewish wife for his safety, highlighting the matrilinear structure of Jewish identity. While Massimo, Gemma, and Sandro die to Nazis, their lineage will live on through Rosa and her British Jewish husband David. Outside of this structure, when Sandro dies and leaves behind a son, Marco raises him as his own. He is very much the father of younger Sandro, but he and Elisabetta also tell him of his birth father, avoiding the secrets that their own parents harbored.