if you have a full ally list, you can keep refreshing the ally list by picking an ally, clicking on Back before a mission starts and repeating until you see a user called Dark Airu, which will have the 4 new knights every event.

Originally Posted by smr

if you have a full ally list, you can keep refreshing the ally list by picking an ally, clicking on Back before a mission starts and repeating until you see a user called Dark Airu, which will have the 4 new knights every event.

This is correct. I actually tried it last night and it worked. You can basically only use this party on easier maps because I think this 4 member party tops out around 17K dmg and the Knights are something like level 10-ish but I see the point that you get to see them in action and see what their skill moves look like before you actually get the Knights.