Here in North America, anyone who is even a semi-serious MMOG enthusiast is well aware that Korea is a major producer. We can all name a number of titles developed there, and probably at least a couple of leading publishers and/or developers. That said, it's pretty safe to assume that few of us are closely familiar with the industry there. So you might find that this list of the five releases I feel have had the greatest impact on the global landscape includes one or more you wouldn't expect.
My choices aren't ranked this time. Instead, I've simply put them in the order they launched in their domestic market. As usual, I invite any readers who have different opinions to share them. I look forward to seeing what your selections are and especially why you picked them.
Nexus: The Kingdom of the Winds
Like probably a large majority of industry observers, I tend to think of Ultima Online as the first MMOG of the modern era. However, a case an be made for Nexus TK, which launched in 1996, the year before. Loosely combining influences from a popular series of graphic novels with elements derived from Korean history and mythology, the tile-based 2D offering was developed and published by a fledgling company that has since become a major global player we are all aware of, Nexon. A North American version of the game entered commercial service in 1998, and is still running.
My primary reason for choosing Nexus TK is that it was Korea's closest parallel to UO in terms of taking the MMO market there from virtually nothing to a significant magnitude within a fairly short time. I've never seen either a hard number or a completely credible estimate, but a good guess would be somewhere in the low six-digit range. What can't be questioned is the vital role the game played in popularizing the category in a country where its penetration rate is considerably higher than here.
In terms of the actual game, Nexus TK is most notable for its rather unusual partially player-run political / control element in which elected users run the justice system and make quite a few lower-level decisions that would typically be handled by GMs. The feeling of power must be pretty appealing; some influential players have reportedly been active in their positions for a decade and more. I have qualms as to whether any such scheme would work in a new release of any size, but the title was definitely a pioneer in this regard. It was also a trailblazer in distributed server architecture, setting a record in 1999 by surpassing 12,000 users in a single world.
Lineage: The Blood Pledge
This is the original appellation of the seminal MMORPG we far more often refer to as either Lineage or Lineage 1. Released in the fall of 1998, it was the title that established another Korean company we all know, NCsoft. The team leader was Jake Song, who had been a principal on Nexus TK. Accordingly, although his name may not have top of mind familiarity for many gamers in this part of the world, he rates inclusion on any list of developers who might be considered the “fathers” of our favorite genre. Perhaps that's a topic for another time.
Here in North America, it's easy to regard Lineage as defunct. After all, the servers for this region were shut down over four years ago. This is a rather NIMBY-esque point of view. In Korea, the venerable MMOG is alive and well. Indeed, NCsoft's 2014 financial reports tell us it generated a very healthy amount of revenue, approximately $240 million. It's interesting to compare this against Guild Wars 2, which is, of course, far more visible to gamers in this hemisphere. Accordingly, many would probably assume it's the bigger earner. In reality, it pulled in just under one-third as much money, around $78 million, which also trailed Aion's $86 million and only topped Blade & Soul by $3 million or so.
Lineage's exceptional, long-lived popularity isn't the only reason it was a no-brainer pick for this list. Another major one is that it opened a lot of western eyes to what was going on in Korea and would soon happen in other nearby countries, mainly China. While many here were focused on the success of EverQuest and thought it the unchallenged top MMOG, NCsoft's offering surpassed it in both number of users and total revenue. A third highly significant consideration is that it showed the viability of building a title using large-scale PvP as its foundation.