Might wanna give RF Online a go. There are three factions total and three times during the day, there is an event called 'chip war' where you have to attack another faction's base and defend your own base at the same time, relying heavily on teamwork to succeed. Upon defeating a faction's base, the player who got the last hit gets the 'chip' of that base and has to run to the center of the war area to deliver the 'chip' to a monster and declare victory for their faction. The winning faction gets a buff for everyone increasing their attack and defense, while the losing factions get a debuff. There are some cases where two factions will team up against one and other things.
Each faction has their own unique race. The Accretian faction is consisted of cyborgs who operate large cannon-like guns with destructive force, the Cora faction consisting of elves who have the unique ability to summon monsters, and the Bellato faction, consisting of humans who pilot a large war machine called a MAU. There are four different classes for each faction, being warrior, ranger, spiritualist (mage), and specialist. (crafter) Except for the Accretians, who don't have a mage class.
Class information here:
http://www.playrf.com/GameGuide/Guid...uide_index.asp
And the main site:
http://www.playrf.com/index.asp
Sorry for the long ramble there. I've really liked this game for it's pvp aspects.
