[Serra Britt]

Grand Chase is a rather old game so It shouldn't be hard to run, though it detests my computer and lags horridly.

Another one you may enjoy is Rusty Hearts, when I first played it, it felt like CastleVania Online. Slow leveling later but it didn't bother me at all because it's rather fun.

And unfortunately I have no idea how Fantasy Earth Zero plays so I can't suggest anything based on this...