Apparently the character of "Kreacher" had been snipped out of "Harry Potter and the Order of the Phoenix," but series creator J.K. Rowling had a little something to say about that.
She was very polite about it, but the author’s advice was basically this: Don’t snip this character out of Part 5, because he becomes pretty important in Parts 6 and 7. So there’s a juicy little hint for all you Potter maniacs out there.
From what I’ve gathered, this Kreacher character is the house elf of Lucius Black. Kinda like Dobby, but evil. Right?
Here’s what director David Yates told MTV Movies: "We took Kreacher out, and Jo said, ‘Listen guys, you don’t have to put Kreacher back, but I’m just telling you, if you want to kind of keep a thread going for six and seven, you might want Kreacher to come back.’ She basically told us Kreacher plays a role in Seven, in a sense. She hinted. We thought about it for five seconds, and he came back."
Source: MTV Movies