Some information on the term
canon: the term was derived from the Greek "κανών", meaning "rule" or "measuring stick". The term was first coined in reference to scripture by Christians, but the idea is said to be Jewish. It didn't quite mean like how we use it today, but that's simply outlining the origins. The modern form of
canon was first used by analogy in the context of fiction to refer to the Sherlock Holmes stories and novels to distinguish those works from subsequent pastiches by other authors. Since then, it's been applied to just about every fandom with a mass large enough to create works of their own, and need a term to point out their works from official ones. So, this is where the term
canon originates from and how it came to be used in the way it is today.
Now, for the RP. I'm fine with a Shadow Game if it provides a better story arc. I'm okay with either of the two girls, as their decks are, I believe, easily searchable for full accuracy. Pick a villain and we can determine the prey based on a story we can discuss involving them. We are definitely not going with OCs, but if you want to be Yugi as well as a villain (or maybe IS the villain, whatever you feel is interesting) then at least make him relevant. Finally, I'd love to make this as realistic as possible when it comes to their decks and dueling styles.
Does that clear everything up for you?
(References on
Canon: )
http://en.wikipedia.org/wiki/Biblical_canon
http://en.wikipedia.org/wiki/Canon_(fiction)