I think Zadnova is a rare, a little mysterious last name. Think it fits him but depending on where you are from you might not like it.
I was more upping for a Dark Mysterious last name, you know kind of like that one Family that lives secluded in a Mansion on a Hill in them Supernatural Series and when people address them they'd say something like "The Lockwoods" and they deal in Shady Stuff or they have a Secret that no outsider should know about, hence the secrecy. though Zadnova is very rare because I've never heard of that name before, it doesn't fit the type of Mysteriousness I was upping for.