After Oslo quickly taken care of Andre and his partner, Ban tries to frighten him by releasing a lot of killing intent. However, Oslo, being a black hound, grew and became very big since black hounds have the ability to change their size depending on how threatened they feel.
Before Ban could kill Oslo, Meliodas stops him, saying that they were the ones who entered Oslo's territory and uses his sword to create an immensely huge dragon-like ethereal creature, which only the black hound can see. As soon as he hound sees the dragon-like creature, he becomes very frightened and flees.
After the battle, Oslo ran back to his master, King, shrunk down to a puppy like state, and the Boar Hat continued on they journey to find King.