The /warp pvp is where most of the PvP takes place on the Main server.
At the warp you can find 2 tokenshops, one of which will reset your PvP statistics HUD. There is also a nearby commandsign which toggles the PvP Statistics HUD, if you want to remove it while you PvP.
The other tokenshop which is the PvP Vendor sells various PvP items such as potions, weapons and armour. The pricing for this villager is a little higher than what most players would sell the items for, providing further incentive to trade or organise auctions with other players.
There are also enderchests on the four cardinal points of the main building, so that if players need to access items from them before they PvP they are able to do so.