Finnish developer Supercell has had a string of mobile successes, including "Hay Day" and "Boom Beach," but none has been bigger than 2013's "Clash of Clans." The competitive multiplayer game is still one of the most popular games for iOS and Android devices. The free-to-play title has racked up nearly $1 billion in revenue since its release, so it makes sense Supercell has announced a new game set in the "Clash" universe. "Clash Royale" is a new foray into the increasingly popular -- and lucrative -- competitive card game genre.

"Clash Royale" is a "real-time multiplayer game" where players collect and upgrade different cards. These cards have different powers with the goal of knocking the rival king or princess from their tower. Victories lead to more points, trophies and glory.  Players can unlock new arenas, challenge other players online, form clans to share cards and create a community to participate in private duels. "Clash Royale" was soft-launched in Canada, Hong Kong, Australia, Sweden, Norway, Denmark, Iceland, Finland and New Zealand Monday. More countries will be added in the near future as Supercell receives feedback about the game.

"Supercell has looked for a fun and engaging approach to player-versus-player gameplay on mobile for years, and we think we have finally found it," the company said on its website. "Clash Royale" includes a few former members of the "Clash of Clans" team, but development of the two games are separate within Supercell.

There are plenty of ways for Supercell to earn revenue from the game -- be it with different ways to purchase chests, cards or upgrades -- but the true test will be how players respond to "Clash Royale."

"Clash of Clans" joins games such as "Hearthstone: Heroes of Warcraft," "Rage of Bahamut" and "Marvel: War of Heroes" in the online competitive card game genre. "Hearthstone," developed by Activision Blizzard, has more than 40 million players with an estimated $20 million in microtransactions a month, according to a Superdata report in 2015.