Who is Kreacher from Harry Potter and the Deathly Hallows and what is their importance?

Kreacher is a house elf. Harry inherited Kreacher from his Godfather. Although Harry and Kreacher do not like each other in the beginning, he later gains Kreacher's loyalty. Kreacher, like all house elves, is obedient. He helps Harry in his search for the locket, and he also leads the other house-elves into the battle against Voldemort.