So what plenty of people have stated about this game is how it requires you to unlock the online multiplayer. That sucks but it's understandable to ensure you know what you are doing before you go play with strangers and ruin their run. It takes about 2-4 hours to speed run to MP if that's what you want to do. You get it after finishing the dungeon with the beholder.
The WORST part about this game is that you have to do it with each character you make. If you want to play a different class with friends online you have to spend about 3 hours with it at minimum to get it online. This was very infuriating to discover and it is not something that many people have been pointing out.