A new report from analytics firm Sensor Tower confirms that battle royale mania spread to mobile, as Rules of Survival (Free) and Knives Out (Free) were the two most downloaded games on iOS in the fourth quarter of 2017 when they released. Both titles, published by NetEase, were downloaded over 15 million times globally. Rules of Survival was downloaded more of the two games, though it wasn’t the top game in the US overall, with Dune! (Free) and Animal Crossing: Pocket Camp (Free) each getting more downloads. However, on a global scale for iOS users, Rules of Survival is a top title.

Over on Android, Rules of Survival isn’t in the top 20 of the most-downloaded apps (which includes non-game apps), but it got enough downloads from Android to rate in the top 20 most downloaded apps overall, with approximately 30 million total since October 1st.

This makes Rules of Survival one of the most popular battle royale games in the world. For comparison, the free-to-play console and PC battle royale Fortnite: Battle Royale has hit 40 million downloads. Meanwhile, PLAYERUNKNOWN’s Battlegrounds has hit over 30 million downloads across PC and Xbox One releases.

Given Fortnite‘s sudden popularity, players and observers should start taking Rules of Survival seriously. This is not like some Asian successes where the publishers fail to replicate the game’s performance in western territories. Instead, this is a truly global hit, and is showing signs that perhaps there’s growth potential from the game’s competitive scene and the PC version as well.

What’s worth considering is whether NetEase’s strategy of releasing multiple battle royale games at once hindered Rules of Survival‘s performance or possibly helped it. Did people choose to download and play Knives Out instead of Rules of Survival, possibly limiting the critical mass of the game that clicked more with players? Or perhaps, did NetEase just give players possibly unsatisfied with one game the opportunity to jump to another title, and corner the market for themselves? Remember that they also have Survivor Royale (Free) and the Windwhisper Survival mode in the MMORPG Crusaders of Light (Free), which all hit western shores on roughly the same day in October. It might be difficult for any competitors attempting to jump into the market to draw players when they already have games that they enjoy.

It’s clear at this point that the battle royale genre is officially a thing, with games seeing success on pretty much every single format except for the Switch. And with that platform’s growth, and the demand from Grammy-winning rappers to get Fortnite on the platform, NetEase might be able to meet the demand for battle royale on Nintendo’s new hybrid system if they get there before Epic or any other competitors can do so.

Can we get a fortnite on switch @NintendoAmerica

— Chance The Rapper (@chancetherapper) February 7, 2018

However, revenue also remains a concern. Rules of Survival is fluctuating in the 100-200 top grossing ranks on iOS, and is top 50 in China, though Knives Out is a top-30 grossing app in China, and barely charting in the US. Compare this to how PUBG sold 30 million copies at $30 each, and has a new crate system. NetEase will have to figure out how to turn these millions of downloads into a massive revenue stream on par with games like Arena of Valor (Free), or perhaps someone else in the industry will do so.