PvP in Nioh is covered on this page. PvP will be released as a DLC shortly after the game's launch. This page will be updated when more is known. Players can check out the Builds page for ideas in crafting optimal setups.
PvP will be releasing on May 2nd for players. There will be 1v1 and 2v2 PvP (part of the free update), shown in the dojo setting. PvP is accessed through the Torii gate and players will have a choice of some pre-made builds to use.