The Acts and levels are vastly larger in Diablo II, so up to eight can play in the same game. Arena games were going to allow more, to permit guild warfare, but these are out entirely now. The closed and open character types are a big new thing. Closed chars are the no-hacking type, and are stored on the Battle.net servers. These servers are called Realms, and only closed characters stored on the same Realm may play together.
Nothing is infallible.
The one serious hack that surfaced allowed players to turn hostile to another player outside of town and it was removed within 24 hours. Unfortunately two features of Diablo II many people were looking forward to didn't quite make the game due to time constraints and will not make the Expansion Pack either. With that said we have kept the sections for your reference. Visit Guild Halls and Arena Games . Reproduction on another server is strictly forbidden.