Hidden City Games, whose online world based on the Bella Sara trading cards we recently discovered, has raised $15 million in strategic venture capital from Rustic Canyon Partners and Trinity Ventures. Hidden City says it'll use the funds to expand the Bella Sara website and for marketing and new product development -- but judging by the investors, who also paired up to support Trion and PlayFirst, it's likely that we can look for more expansions to the horse-themed Bella Sara online presence, possibly even in the virtual world or microtransactions arena.

“With more than 30 million trading cards sold worldwide and more than 1 million registered website users, Bella Sara is the first trading card game to capture the hearts and minds of girls,” said Michael Song, a partner at Rustic Canyon Partners who's also joined the Hidden City board of directors.

Gus Tai, general partner at Trinity Ventures who also joins Hidden City's board, added “[Hidden City CEO] Peter Adkison understands how to build a global retail footprint, and we are bullish on his plans to leverage Bella Sara’s in-store presence to grow its registered-user base." Tai also noted that Hidden City has some 65,000 retail points that drive traffic to the Bella Sara site.

Adkison is also the founder of Wizards of the Coast (Pokemon, Magic: The Gathering), which was sold to Hasbro in 1999.