Board Game Arena

For games without a competitive mode and thus no ELO ranking to use as a threshold for Expert/Master rank, how does one reach Master rank?

Each cooperative game uses it's own "formula" to assign elo. For some it's a plain +1 for every session, for others it may be + or - depending on the result. In any case, the score is there, and Master means 700 or more, it's just not displayed.