But while Dobby is a beloved and memorable Harry Potter character, he wasn't the only House-elf in the saga. Kreacher, the Black family House-elf, was first introduced in Harry Potter and the ...
RAB is Regulus Arcturus Black, known to be a part of the House of Black.
Harry Potter is lauded as the brave and successful ... and wondering whether Kreacher might bring him a sandwich there." Kreacher, a house-elf, is essentially Harry's personal slave.