When we at Riot Games set about building PC online multiplayer-centric title League of Legends, we did so with the lofty goal of creating a high-quality competitive experience with a rich, evolving metagame and low barrier to entry. We believe these features are essential for a free-to-play game aimed at core gamers to be successful.

Multiplayer Online Battle Arena (MOBA) games like League of Legends have their roots in the modding community. And while players are more than willing to accept a single map from a modder, they tend to be more demanding when it comes to virtual real estate in a full-fledged product. As a result, before League of Legends officially released, we set about working on our next battlefield.

It is our belief that in order to maximize the success of a multiplayer map, the new maps would need to be available to everyone. Therefore, they're not something that can be explicitly sold to players in our virtual store. They do, however, still play an extremely important role in a game that is operated as a live service.

First, and most importantly, they provide new, fun, competitive options for players by providing an alternative to the core experience.

A new battleground can also revitalize the interest of players who had previously moved on, motivate players to purchase new items better suited to this new battlefield, draw in new players with the promise of unique gameplay, and just generally increase the fervor of competition.

So, while content that isn't offered in the store doesn't directly drive sales, new maps are certainly important and can play a role in the game's growth.

A champion doing battle on Summoner's Rift, the first map released for League of Legends.

Releasing a new map, however, can be a more daunting task than it sounds; particularly if you want it to be balanced and ready for competitive play. From the time a new battlefield is just a twinkle in a designer's eye, to the time players are poised in a pitched, online battle with one another, there's a lot of work that needs to get done. So what goes into making a balanced and innovative MOBA map? Well, to start with, let's talk about what makes a MOBA game tick.

What is a MOBA?

MOBA games harken all the way back to the days of the original StarCraft, when the custom map Aeon of Strife was created. This map streamlined the traditional real time strategy paradigm by placing the opposing bases under the control of the AI -- each base spawned minions to attack the other down predictable, preset paths called "lanes".

Allied with each of these two AI-controlled bases were two opposing teams of players, with each player in command of a single, powerful hero unit (or "champion"). Without the intercession of the players, the two bases would fight to a standstill, neither making any headway towards the other.

Aeon of Strife, however, was subject to the limitations of the StarCraft map editor, and as a result, didn't possess enough intricacy to hold the lasting attention of a hardcore playerbase.

As a result, the MOBA genre didn't truly begin to blossom until the birth of Defense of the Ancients, a community mod built using the more powerful Warcraft III world editor, which allowed for the creation of much more robust champion units. Players could now earn money and experience for their champions by killing enemies, gaining levels and acquiring equipment to help them wage war. It was here that the standard paradigms that would define the genre would begin to take shape.

A game of Aeon of Strife, the forefather of the MOBA genre, in progress.