At BlizzConline 2021, the Diablo 4 team discussed enemy camps, the open-world, mounts, and PvP.
In a What's Next segment for Diablo 4, the development team showed off the Rogue class a bit more, and also discussed open-world aspects of the game as well as PvP.
According to Blizzard, there will be plenty of exploration in the open-world, and with an open-world, the team can dive into how Sanctuary fits together, like the player being able to ride from Scosglen to the Fractured Peaks using mounts.
One of the cools things about mounts, is there will be different horse breeds and other mounts you can find throughout the world through completing puzzles to finding hidden locations, or even slaying particular kinds of monsters. You will also be able to find things to customize your horse with such as armor, hoof plates, and trophies. There are lots of ways you can personalize your mount to make it feel like your companion.
There's more you can do with mounts than just ride them. For example, the Rogue can leap up into the air off of the mount and fire down Rain of Arrows to destroy everything. Your mount can't take damage, but if you are attacked while on horseback, it forces you to dismount and engage.
Another aspect of the open-world is camps, which are basically a stronghold of evil out in the overworld. At these camps, you can expect all sorts of monsters and bandits whose sole purpose is to take over the area. You will wander to these spaces and begin to reclaim them for the people of Sanctuary. Each will have its own story, and unique fixed place in the world.
Quests are something that you can come across randomly in the world, but camps are a permanent fixture that when you come across it, can have an impact on the open-world that everyone can see. Once you have defeated that evil, you basically unlock that camp and create a new waypoint that didn't exist before. Suddenly, all the marketplaces will open up, you will have a blacksmith, and a vendor in a location that previously did not exist. New quests may pop up, and there may even be new stories to be told. Dungeon entrances can even appear in these places afterward.
Basically, you are helping re-settle these areas in Sanctuary when you take these camps back from the enemy.
With PvP, there will be areas called Fields of Hatred in the open world you can freely walk into that kind of consume you and make you turn against other players. PvP is not mandatory, as these places will be optional for the player to go to. Here, you can collect Shards of Hatred by killing monsters and interacting with the environment, not just by killing other players.
As you earn these shards, they will be in an unpurified state and will need to be brought to a Purification Event in order to turn them into a currency you can use in the small encampments around the Fields of Hatred for armor, trophies, or other content. When trying to purify a shard, it will alert other players who will come in and try to attack the player and take their shards before the ritual can be completed. Once purified, they are yours to keep, but before they are purified, they are fair game to other players in PvP.
The more you turn against other players, you will turn into a Vessel of Hatred. Once this occurs, everyone within a large radius of you will see you as a threat on the map. They will get a bonus for killing you, so when that occurs, you have a set amount of time you need to survive. If you are able to survive that amount of time and escape or defeat those trying to destroy you, there will be a very big bonus at the end.
According to Blizzard, this just scratches the surface of what to expect in Diablo 4.