what games are considered korean mmos?
Ragnarok, Lineage/Aion, and probably anything from Nexon/Ntreev.
I'll add Granado Espada to that. I was in the beta for it and while the fact that you have 3 characters at your control was very fun, the grind is what made me stop right at the end of the beta.
Heck, with the recent system changes, the game supports botting =/