WHAT THE FUCK??!!
So it seems that this will be it own thing. You play as preset heroes, the level change between sessions and has a focus on coop.
I think nightreign is to elden ring what legends mode was to ghost of Tsushima.
A good move in my opinion. With the mangas they showed that they are not scared to make something non-canon.
I often had the thought that they should make a PvP arena standalone. You can choose from all the skills and weapons and such from across the games and balance for that and focus on netcode.
But it still seems to be in the game. There is a shot where it lies broken, maybe we repair it and the can play as it.