The final event of the day, the Clan war, it wasn't exactly as the name suggested, it was a 10v10, an "all-out" battle between two clans. The clan leader was in charge of assigning the individuals who would take part in this event, it was his/her choice as to who they wanted to send.
It wasn't necessary that the leaders sent out only the strongest or the members with the highest level, the entire goal of this event was to not only test the clans' strength but also to test the decision-making of the leader.
