Zepek is Jill's alcoholic father. Once a member of the army, but now a cruel father to Jill and a horrible husband to his wife who is also drunk most of the time. He managed to hit Guts with an arrow when Guts was about to finish off Rosine.
He is a violent drunk who is cruel to his child and wife, however he served in the army, showing he has some bravery. Whenever Jill object on him he would beat her saying that she has no right as he fought to protect her and her mother, but his word can't be taken seriously as he is drunk most of the time.