Since this weekend and the coming week has been/will be a bit busy, this latest post from me is something I’ve previously written, but it was sort of hidden away on a different site. I’ve reposted it here for your reading pleasure.
There are basically 3 types of endgame elements most modern MMOs have available: PvE, instanced PvP, and open-field PvP. The rest of this article assumes we’re discussing the last, open-field PvP.
Many MMOs have opted to have two player factions: World of Warcraft is probably the largest, but many others have also used a similar model, including Warhammer Online. A two-faction system has certain advantages in its simplicity - it’s always clear who the enemy is, it’s the simplest to write separate story lines for, and it has the least redundancy for level areas (if you choose to have faction-specific quests or areas, which are a near-necessity for any kind of immersion factor).
But a three-faction system has one key advantage that almost single-handedly makes it far more attractive for any game looking to create an environment for meaningful world PvP: it’s self-balancing. Whenever any individual faction gains the upper hand, they automatically become the outnumbered, which means that overall control will almost assuredly continue to change hands over time. No single faction is likely to become so much larger than the others that it maintains constant dominance, simply because it would have to attract players at something along the lines of a 2:1 ratio of any other faction to be able to maintain population superiority over the other factions combined.
Furthermore, a three-faction system has the advantage that there’s not a harsh penalty for being the “underdog”. Sure, the smallest faction might not maintain control as often as the other two factions, but whenever they don’t have control, they’re also not the main target. Thus you don’t have a system which devolves into one “bully” faction picking a smaller one, because the bully faction themselves is outnumbered by the greater opposition.
Since no faction is likely to hold on to the reins of power for too long, it’s easier to implement bonuses for those who do currently have power without throwing balance out the window, which means it’s easier to make world PvP objectives which actually have incentive to fight over them.
Of course, any number of factions greater than 3 also works for this, but more factions also make things more complicated and splinter the playerbase. Depending on how your game is designed, this can still be feasible (see EVE for a good example of a many-faction system, though Corps and alliances), but should be undertaken with care - and is not so conducive to games which have a less sandbox approach than EVE.