Gree said today it is happy with a publishing partnership for Knights & Dragons, a mobile game that yielded $5 million in revenue in a 30-day period.

Japan’s Gree published the fantasy role-playing game as part of a partnership between its San Francisco studio and Vancouver, Canada-based Iugo Mobile Entertainment. The partnership is now one of the most successful publishing relationships in mobile games, Gree said.

“Our relationship with Iugo, a leader in building high-quality mobile games, is a great illustration of how publishing can work and is a template for future partnerships,” said Naoki Aoyagi, the CEO of Gree International in San Francisco. “A core part of Gree’s strategy is developing strong publishing partnerships with some of the industry’s top development talent and we aim to keep building more hugely successful relationships like this one.”

Knights & Dragons also one the “I can’t quit you” award in Google’s first player’s choice poll.

“Between that revenue number and the recent Google award, we are confident that we are delivering the game players are looking for,” said Hong-Yee Wong, CEO of Iugo Mobile Entertainment. “The success of our partnership with Gree comes from both parties offering close and regular communication and a willingness to learn and share with each other. It is a foundation that needs to be built to ensure the publishing relationship works. Knights & Dragons is proof of how far the right game can go with the right teams behind it.”

Back in July, Gree said that Knights & Dragons had surpassed $1 million in monthly revenue. Since then, the companies have added new features, content, and in-game events. It also tracks key metrics to continually improve game experience, retention, and monetization.

While the result is good, it isn’t quite as good as GungHo Entertainment’s Puzzle & Dragons game, which is generating revenue of around $5 million a day.