PvP

Definition

PvP means "Player versus Player" ... and is basically a feature where you can attack logged out "sleepers" either in the fields, the inn or the dwellings.

Some other locations might be added, too.

There are certain setups of Orochimaru kill points to make you a strong PvP fighter. A large amount of hitpoint will also help you very much.

Also note that there are players who become sitters, making them incredibly strong in PvP.

"Live" PvP

...is not possible, as the game itself is a server-based passive game, means you start an action, you get feedback. To sync two players and not let them do anything else (one might die, though) is virtually impossible, one might log / time out and produce a deadlock, leaving the other player in a battle with no way out.

The chances of cheating are also too great, so it won't become a new feature.