The article introduces a new concept called the risk-based core for cooperative games with uncertain payoffs. Instead of always expecting the worst outcome, this approach considers the risk of deviating from the original outcome. By comparing the payoff of staying with the original outcome to the risk of deviating, the researchers found an inclusion relation between cores of games with increasingly conservative players. This concept is also useful for studying cooperative games where the value of a group depends on the entire group's performance. The researchers discovered many familiar inclusion relations between different core concepts, but the inclusion of the optimistic core in the optimistic recursive core is not always guaranteed.