let me say this,
in my opinion Knight Online has the BEST PvP system i ever saw in a mmorpg.
and actually, the whole game is about PvP.
U level and collect coins and good items, just to be able to equip your character godly for PvP.
There are wars between the two nations, there is a PvP map (Colony Zone), there is a Arena (there is also the abyss dungeon, where u can attack people from other nation to, but its considered lame)
U have several options to gear up your character, to be able to perform MAX against every different character. (can wear specific weapon defensive gear)
There is alot to do. A large variety of monsters (mobs), that u can slay and collect items from. There is so many people, that u can form a party at any time of the day.
The market is huge, when u have enough money, u can find whatever u seek in a instance, and so on...
in short, its a great game, u will enjoy it.
but there is only one downside,
85% of the time u wont be able to login because of the Premium Membership logins.
There are certain times (read almost always) that only Paying customers can login,
so if u like the game, a premium membership is a MUST if u wanna play it. Its not expensive.
and the fact that alot of the paying customers are turks, u might bump against a couple characters who doesnt speak english at all,
but its not hard to just ignore and avoid them

anyways,
if u have more questions,
or if u need a helping hand with the start during the game,
i can help u explain a few things.
ciao