Given how the book operates as a recollection of Wiesel's experiences during the Holocaust, all of the characters stand out in his memory.
The opening pages detail the significance of Moshe the Beadle. His initial warnings and the disbelief people displayed stand out in Eliezer's mind as a foreshadowing of things to come. Eliezer's father stands out in his memory, as well. Initially, Eliezer looks at his father as a leader of the Jewish community in Sighet. Once both are taken to Auschwitz, the rest of their family dies and both struggle to survive. As their time in the death camps increases, Eliezer's father stands out in his mind as he becomes weaker and Eliezer must act to protect both of them. Madame Schachter's vision of "fire" also stands out in Eliezer's memory. Her warnings to the other Jewish people in the railway car assume a prominent place in Eliezer's mind. Additionally, the way in which the other people in the car beat her to keep her silent is something else that stands out in Eliezer's mind.
All of the people that Eliezer encounters in his experience assume importance in his memory. Juliek playing his violin and Akiba Drumer asking the other prisoners to recite the Khaddish for him are two such examples. It is deliberate that all of the characters stand out in Eliezer's memory. He ensures this in order to validate their experiences. The Nazi attempt to silence their voices is met with resistance in the form of Eliezer's memory. He seeks to give voice to those who lacked it. In doing so, he challenges the Nazis and ensures that future generations will bear witness to the past in the hopes it is never repeated.