Launched back in the year 1998, Lineage 1 is still the main revenue source for NCsoft in the 2nd quarter of 2013. That is a huge 15 years of live service! The next major revenue source, Guild Wars 2, is actually miles away according to the latest financial report seen below.
NCsoft has quite a few new titles in development, including a co-development effort with Nexon for Mabinogi II: Arena, a mysterious Unreal Engine 4 FPS, a major investment in Molten Games, WildStar and the much anticipated Lineage Eternal.