Fire Emblem: Heroes has already made millions.

Intelligence firm Sensor Tower has stated that Nintendo’s second mobile game has grossed $2.9 million in its first day. It launched for iOS and Android on February 2. The free-to-play game takes Nintendo’s popular strategy series to mobile while encouraging players to spend in-game currency or real money to build up an army of heroes from past games in the franchise.

For comparison, Nintendo’s first mobile game, Super Mario Run, made $8.4 million in its first day. That game debuted only on iOS. Still, it may not be a fair comparison. Mario is a much bigger brand than Fire Emblem. Also, Super Mario Run was behind a $10 pay-wall to access most of its content, so many players who downloaded it on the first day immediately spent $10. Fire Emblem: Heroes’ players, however, may spend more money, but over a larger period of time.

A better comparison may be against another popular mobile strategy game, Clash Royale. According to Sensor Tower, that game made $1.4 million in its first day. Fire Emblem: Heroes also earned 2 million downloads in its first day, the same amount that Clash Royale had in its debut. Super Mario Run had 6 million downloads on its first day.

So, this is a strong launch for Heroes, but it needs to retain players if it wants to be a long-term success in the $40.6 billion mobile gaming industry. And it could do that — especially in Japan. Heroes is debuting at a time when a long-time Japanese behemoth in the mobile space, Puzzles & Dragons, is beginning to lose popularity. That could create an opportunity for Fire Emblem to become a hit in that country, where the series has been around since 1990, and where the average mobile gamers spends more money than anywhere else in the world. According to Sensor Tower, most of Heroes downloads have come from Japan.

Fire Emblem didn’t debut in the U.S. until 2003, but it has become powerful tool in Nintendo’s stable of franchises in recent years thanks to the success of 3DS games Awakening and Fates.