In addition to Harry, Ron, and Hermione, apparently we can expect to see Bellatrix Lestrange (Helena Bonham Carter) and Lord Voldemort (Ralph Fiennes) himself in the new scenes as well. “Of course you have He-Who-Must-Not-Be-Named making an appearance…Helena [Bonham-Carter] supports him as one of his team. And then we have our main heroes appear as well. You get to meet all the great characters from the stories,” Gilmore continued.
[source]
WHAT
said the HP fandom
