I played this game called Emil Chronicle Online and there was this war called “Knight Training”.
Everyone are given a choice to join 4 faction (North South East West) in the war. They are not bound by guild neither by faction.
For example, I can fight against my own guildmate in the war if I choose to fight for North and my friend choose to fight for another faction (South East or West). In the next war, I do not have to choose North again, I can change to another faction. All of the war points (highest kill, damage dealers, damage taken, etc) belong to each player, overall score belong to the nation, but not to a guild.