Daniel Radcliffe will not appear in HBO's new Harry Potter series, but if he did, he knows who he'd like to play.

Sirius Black ... Arthur Weasley thinks he's escaped because Harry still stands in You-Know-Who returning to power. "When you [Harry] stopped You-Know-Who, Black lost everything.

SEE ALSO: 5 articles that'll only make sense to true 'Harry Potter' fans In particular, Thériault had some thoughts about how Molly Weasley and Sirius Black are portrayed in the series' fifth book.