I really don't think Ace is lying here. I'm trying to think of the only scenario where claiming knight falsely would help here. Only thing i can come up with is he's the medium or seer or something, and called knight just to take suspicion off of him, figuring the wolves wouldn't attack him. But then he'd have to assume the real knight wouldn't say anything and read what he was thinking, which i'd assume any other knight would be like "No fucker, i'm the knight, you're a wolf, die".

I know that the knight can survive a wolf attack, or a lynching, can he survive the Hunter's shot to the head? I guess if that happens, there's a way where Ace is the medium, found out Stamkos was the knight in dead chat (shot by hunter), and claimed it to protect himself. Probably over thinking, but it's midnight.

Point is, i think we can trust Ace, as hard as that is to say out loud