House-elves have their own brand of magic, as do many other magical creatures. Their magic allows them to perform tasks, such as Apparating, where wizards cannot.[1] More than just a mere housekeeper, a house-elf is a ruthless protector of the master, and will attack threats with great fury and strength.
When Harry Potter inherited 12 Grimmauld Place and Kreacher in 1996, Albus Dumbledore wanted to test to see if Harry had truly inherited his godfather's possessions. Harry was told to give Kreacher an order. At the time, the only thing he wanted was for Kreacher to shut up. He told him to do so, and instantly, Kreacher almost choked on his own words.
To test the security around the locketHorcrux in the 1970s, Lord Voldemort required a house-elf for the job, and Regulus Black nominated Kreacher. After using Kreacher for his purposes, Voldemort left him there to die. Bound by the laws of his kind, Kreacher was able to Disapparate out of the cave and return to Regulus because Regulus had told Kreacher to return after the task was finished.
In 1993, Dobby protected Harry Potter by using his magic to throw Lucius Malfoy across the floor, and in 1994, Winky used her magic to bind Barty Crouch Jr. to her,
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