[Lotm Newbie] Are the Tarot Club members randomly picked by the Grey fog?

I'm on Volume 4 of LotM rn but feel free to spoil me if the answer to my question requires it.

How are the members of the Tarot Club selected? Like the red stars that Klein can access above the grey fog that represent each member, are those randomly picked? Or is there something special about each member?

I recall that each member had some artifact that broke or disappeared after they joined or something like that, like Derrick's crystal ball. And Alger even commented on Cattleya having a globe like object that looked similar to the bottle he had which shattered after the first Tarot Club meeting. So is there some connection?

I'm pretty sure this might be explained later but I have no patience😭🙏

(There is also the chance that this has already been explained but I have forgotten 💀)