Final answer:
Juliek is a character in Elie Wiesel's 'Night' who is a violinist. Before he died, he played a piece of music which profoundly affected Eliezer, highlighting the loss of culture and humanity in the concentration camps.
Step-by-step explanation:
Juliek is a character from Elie Wiesel’s novel Night, which is a work of fiction within the Holocaust literature genre. In the story, Juliek is a Polish Jew and a fellow prisoner with the narrator, Eliezer, in the Nazi concentration camps.
He is a musician by trade, a violinist, whose presence in the book is a stark reminder of the loss of culture and humanity amid the horrors of the Holocaust.
Before Juliek's death, in one of the most poignant scenes of the book, caught amidst the chaotic and suffocating conditions of the crowded barracks, he finds the strength to play his violin.
The piece he chose, Beethoven’s concerto, serves as a final assertion of beauty and art in defiance of the utter brutality surrounding him.
This moment deeply affects Eliezer (referred to as Eli in the question), the main character and narrator, underscoring the loss of identity and despair the prisoners feel yet providing a brief respite through the beauty of music.