The Witcher Battle Arena was a free-to-play multiplayer online battle arena (MOBA) video game developed and published by CD Projekt Red. The game released for Android, iOS, and Windows Phone devices in 2015, and was playable until the end of that year when the servers were closed.
The Witcher Battle Arena is a multiplayer online battle arena set within the universe of The Witcher. The game matches use of touchscreen controls. The game features eight heroes—playable characters from the series—each with three skills. Additional content can be unlocked quicker through microtransactions.
Source: Wikipedia, "The Witcher Battle Arena", available under the CC-BY-SA License.