Dobby

Dobby
was a house-elf who belonged to Lucius Malfoy until Harry Potter freed him.

He was often beat by his master and beat himself when he did something against Lucius.

In The Chamber of Secrets, Dobby tries to stop Harry Potter from going to Hogwarts by keeping Harry's mail from getting to him, but he failed. He then met Harry later on and told him about the Chamber of Secrets.

Later, Harry released Dobby from his evil master.