[ He can't, not really - and not hardly because Merlin knows far more than Arthur, still, and don't think that doesn't weight heavily upon him most days - but when does Arthur ever allow himself any fun when there are important matters at hand?

And for the King of Camelot, there are always important matters. ]

You know of the Lady, then. That puts you a fair few months ahead of me.

[ Assuming Merlin explained the basics, Gwaine should know what he means. If not, Merlin being useless isn't entirely news. ]

Care to explain the toy sword there? I'm giving you the benefit of the doubt and assuming you didn't lift it from one of the native children.

[ And it must be related to the state of his health in some manner. Not having eaten in a week because he's been hunting with a wooden sword doesn't seem the likely situation. ]