Night is full of transformations—people becoming something other than human. What transformation takes place in the last two lines of the book?

The Nazis transformed Eliezer into a living corpse, a shadow of his former self, and surrounded him with constant death and misery. They killed his family, reduced him to base, animal instincts, and denied him his humanity. No matter what revenge Eliezer and the other prisoners may seek from the Nazis, there is no way that they can undo what has already been done.