It's the franchise that's selling, not wether it's a first or third party game. Even though it's an MMO, Dragon Quest X still has the Dragon Quest name attached to it and will sell Wii U's. It's also worth pointing out that third party franchises like Dragon Quest, the Tales series, Final Fantasy, and Monster Hunter are popular than Nintendo franchises in Japan. Now, just imagine how sales would be if it were a traditional DQ game.
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