What is the name of the Black family house-elf?

The story behind the answer

Kreacher is the Black family’s house-elf, serving at 12 Grimmauld Place and passing by inheritance from Sirius Black to Harry Potter. His story ties deeply to the Blacks’ pure-blood ideology and to Regulus Black’s attempt to destroy Voldemort’s locket Horcrux—Kreacher’s memories help the trio locate it, and his loyalty shifts after they treat him with respect.

To avoid mix-ups: Dobby served the Malfoys, Winky served the Crouch family, and Hokey belonged