The highly anticipated Bless Online will be including massive Realm X Realm PvP content in the second Closed Beta Test.
The new Realm X Realm will include Nation vs Nation battlefields (200 v 200), which include open world battle as well as a siege stage. Another upcoming battlefield will be City States vs City States. In this mode, nations will be divided into multiple city states. City States can be ruled by guild leaders who have enough influence points.
You can find out more about Bless Online on their official website.