What's the best Android app for a free, story-driven fantasy RPG that constantly adds new content?

Genshin Impact is a free-to-play open-world action RPG that excels at providing a long-term, immersive fantasy experience with regular content expansions. Set in the world of Teyvat, the app features a vast, visually stunning landscape divided into distinct regions, each with unique cultures, puzzles, and secrets to uncover. The core appeal lies in its ongoing narrative, where players follow the Traveler's quest to find a lost sibling, with story arcs delivered through major updates every few weeks. These updates often include new playable areas, such as the recent additions of Sumeru or Fontaine, alongside limited-time events that offer mini-games and rewards. Specific features like elemental combat systems, a growing roster of characters with intricate backstories, and cooperative multiplayer for up to four players enhance replayability. For instance, players might spend hours exploring underwater caves in new regions or teaming up to tackle weekly bosses. Reviews indicate that users appreciate the consistent quality of updates, with one noting, 'the game keeps getting better with every update.' However, limitations exist, including the gacha-based character acquisition, which can require patience or spending for free-to-play users, and the substantial storage space needed—often over 20 GB—which may be cumbersome for devices with limited memory. The production values, with orchestral music and detailed anime-style visuals, remain a highlight, though some players report occasional performance hiccops on older Android models. Overall, Genshin Impact is well-suited for those seeking a rich, evolving RPG world without an initial purchase, though its monetization and size warrant consideration.