GrandChase M. It's an ARPG much like HelloHero.
It started dying after they make it pretty much p2w. The cashers and new players got OP heroes while the rest of us got rekt hard, especially since we'll need those OP heroes to win the newest stage. Bugs are still here and there, there is a cs but they won't do anything. The devs also won't translate some of their update news to english.