Hows the population? Community?
Decent pop. The community on the forum has lots of people that barely speak English, like the usual Korean rpgs, and that annoys me.

Graphics?
Pretty decent for a free game, it uses the havok engine. The blood and ragdoll deaths are the only unique things about this game.

Gameplay?
Generic WoW clone, but not as deep or polished as WoW.

Grind?( rate 1-10, 10 means it takes 1 hour to get 1% at lvl 20)
I'm only at level 10, so I dunno.

Base on parties or can solo fine?
Soloing is best with certain classes, read the forums to figure it out. Parties are only for dungeons, unless you have friends playing.

item mall overpower and expensive?
Dunno, haven't looked at it.

lag issues?
Yes, it's noticeable but still playable.