It's important to get the wording right here. In death camps such as Auschwitz, Sonderkommandos were work units composed of Jewish prisoners who were forced by the Nazis to aid with the disposal of gas chamber victims. Kapos, on the other hand, were Jewish prisoners in charge of Sonderkommados. They were also given responsibility by the Germans for keeping good order in the barracks.

Kapos, like all the other Jewish inmates of the camps, were victims, but they were also victimizers, using violence and brutality to maintain control over the other prisoners. As such, they were hated, damned as traitors for helping the Nazis oppress their own people.

In Night, Elie and his father are regularly subjected to violent treatment at the hands of one particularly sadistic Kapo by the name of Idek. The man is so unhinged and full of rage that he beats up Elie's dad for asking to go to the toilet. However, not all Kapos are like Idek. There's one in particular who stands out for his humanity. Sadly, he was executed after being caught hiding weapons for a prison resistance movement.