Ark Sphere is one of the most anticipated MMORPG for tablets and smartphones. If I had to recommend a Korean MMORPG to play on the go, then it would definitely have to be Ark Sphere Online. It's one of the biggest MMORPG's that you can play on with over 100 players in one zone. The game offers a lot of features such as raid boss battles, crafting system, large open fields, high quality graphics, party system, field bosses, avatar system, and more. Ark Sphere is packed with all the MMORPG features that you're looking for! Unfortunately, the recommended Android spec for the game requires 2GB of RAM due to the high quality graphics it has to offer. I hope the iOS version comes out soon!
Google Play: Link