Invincible season 4 aired earlier this year and saw the return of several major characters. However, fans were left a bit confused when one of the main cast members didn't return to voice William Clockwell, Mark Grayson's loyal best friend.
Girls star Andrew Rannells was the original voice actor, starring in the show for the first three seasons. However, in the fourth outing he was replaced by comedian Brandon Scott Jones. Now it turns out that Rannells isn't sure why he wasn't asked back.