In the original screening of Gotham Knights, we saw a player invite a friend to co-op to play together. And it is also for two people that the adventure is built, even though there are four playable characters.
However, it should be said that the description still reads: “Patrol Gotham’s five distinct boroughs in solo-play or with one other hero”. We will have to wait and see what simply applies, but given all the huge delays and the fact that the versions of Playstation 4 and Xbox One are rumored to have been abolished, it would not be entirely unreasonable for co-op for four to be added.
Today at 15:00 we will also see a little more from the game in a stream dedicated to the characters Red Hood and Nightwing (Batgirl and Robin were already shown in 2020). Hopefully we get more details then.