Square Enix said Thursday that its Nintendo DS role-playing game Dragon Quest IX: Sentinels of the Starry Skies shipped 5.3 million units worldwide as of December 31, 2010, according to Japanese-centric gaming site Andriasang. Passing the 5 million mark makes Dragon Quest IX the best-selling Dragon Quest game ever, the site said. Today's figure is just the latest major sales milestone for the game. In Dragon Quest IX's opening weekend in July 2009 in Japan, the game sold-through 2.34 million units. In its first three weeks on the market, it had already sold 3 million total. By mid-August 2009, sales were approaching 4 million. The game, developed by Japan's Level-5, launched in North America and Europe in July 2010, a year after the Japanese release, and in Australia in August last year. To date, the Dragon Quest series has shipped 57 million units worldwide since its Japanese debut in 1986.