Multiplayer Game Development

I want help to build a multiplayer PC game in a 3D environment. The game can be either 1st or 3rd Person perspective. I want it to be an RPG with Dungeons and Dragons style character development and skills, but act as a shooter game akin to Tom Clancy's 'The Division' where it is predominantly player vs environment/non player characters. I need random loot spawns of various levels of rarity as well as some recourse for dying, possibly some rogue-like elements where each progression through the game is different and death resets your items/load out. However, I would like to retain all stats/level ups even after player death. Possibly some kind of class system that each level independently and not synchronous across all characters. This games needs to be at minimum single player, but I would like it to host up to four players simultaneously.