since it goes f2p, i might as well try. but i like to know does this game has pvp ? is it like WAR that you have open bettleground and defence the base / flag and etc..?

The game uses a heroes vs heroes battleground style with different kind of scenarios like arena team vs team, heroes vs zombies (where dead heroes come back as zombies) and also a deathmatch pvp.  During the Bloodmoon event, you can try the werewolf vs hunter pvp, as far as I know it's the only open world pvp there is.