Dsod is part of duel monsters moron it's the same characters just like the game begins with cards from pyramid of light movie yugi kaiba lvl up 40 rewards
I doubt those "series numbers" are intended to be connected to the identifiable series names, they're probably headers of their own alongside them. Probably as placeholders in case they want to add more worlds based on existing series, like a Waking the Dragons world or a Barian-themed Zexal world or whatever.
That being said, I know nothing about the game's data structure.
no name
Anoymous
