Xokingdoms as of right now is made of two kingdoms, Arachide and Sovereign.
This Kingdom is under King Random, and has the two factions Salvador and Omni in it. Omni is run by Jcreasonfrodo, and Salvador is run by SireCreed. Omni is located in the pvp sector of the map, therefore you can pvp there. But Salvador is located in the non pvp sector of the map, so you cannot pvp there.