The "fans" are some families with their kids and people living outside of the city in the countryside, RB got no ultras, no real fans or fanculture whatsoever, you can sum it up like this: they are competing with the Zoo and other atractions here for families. Thats the tier they are into. And trust me, RB don't stand for East German football culture, they are a company running a commercial by shamelessly filling the gap of missing real big football cause of the aftermaths of the revolution. If you want East German football take a look at Union Berlin, Chemie Leipzig, FC Magdeburg and so on. There isn't any love involved with RB, its more a "yeah ok now we can see Bundesliga in a stadium nearby again", thats just a pragmatic sight on it, love gots nothing to do with this. Love and passion, this you get at real clubs, which exists a lot in East Germany. RB is not an East German club, its an invader taking advantage of a city not having big football for a long time and the whole area.