In a sandbox MMO, game progression is very hard to define. In a game with no levels or classes, it is nearly impossible. Players can explore the world at their whims, and they progress through their surroundings at their pace. Additionally, it is very difficult to say where players will begin the game, since they can choose any city their race has conquered.
The most that can be planned is that players will begin the game in a city controlled by their race. From there, their story is their own.
The amount of content that can be soloed in the game falls somewhere between Everquest and WoW. Depending on how the character is built, most every combat character should be able to solo wolves and bears to advance their skills, as well as building wealth through hunting.
Enemy players, whenever they are found, can be attacked and possibly soloed. This grants skill just the same as PvE combat. Many enemy NPCs can be soloed, especially merchants travelling to a new area or guards on patrol.
The goal of the solo game is for a player who is by themself to feel like they are able to make small contributions to their race without joining with any other players. Additionally, all sorts of gathering, crafting, and diplomacy can be done solo.
Players should be able to do most things in the game reasonably well, but doing them in groups will increase their effectiveness. They can also join with NPCs that are doing things like sieging cities, since a player clearly cannot do that solo.
Grouping will be possible for gathering, some crafting, and all forms of combat. Getting together with friends or members of one's race to accomplish greater tasks is a core of the game. Small groups will be able to positively influence the game for their race.
In PvE, a group could take on an angel or demon that they find, attack a cave or small landmark controlled by another race, or work together to deliver a poisoned food supply or cursed weapon cache.
In PvP, a group could hunt down enemy players, harass supply lines/farms of an enemy race, or try to burn a small enemy city.
Raids will mostly focus on the angel and demon isles to the north, or raids against medium-sized cities belonging to enemy races. They can also be used to rapidly take over lots of territory.
In PvE, a raid could bring down several small holds or wipe out a portion of an enemy race's angels. It could also join together with other raids to bring down a large city.
In PvP, a raid could take out a medium-sized city or simply meet an enemy raid on a field of battle for control of an important choke point.
Epic Scale Battles
HND introduces something beyond the raid, something more carnal, unorganized, and exciting. Epic scale battles involve huge numbers of forces, both NPC and PC. When a great NPC leader marches forth with 100 NPCs to take a main enemy city, and he is joined by 90 players of his race, an epic scale battle is set to take place. This is the place where Miracles are called down, great leaders are slain, and the world is changed. Siege weaponry is often brought forth, and a vast portion of a race's NPC resources can be lost or won (through prisoner capture). These are the battles that change the world, and players of all skill levels can be involved.