Talk:Armor/@comment-202.49.20.41-20131127041351/@comment-24108837-20131201214028

It means that you have at some time in the past put that armor on a knight in the set used for the Summoning Stone or the program randomly picked that armor to put on a knight tehre. It works similar to the Arena or the Epic Boss fights. If you really want to use that armor you can safely do it. The knight in question will be re-equipped with another (random) armor if it can't wear this one anymore. That other armor may be a very low level armor that just happens to contain the right element for that knight. So prepare to see that message again at some unexpected moment.

If you want to manually equip your knights in the summoning stone with other armors you are out of luck: You will have to pay gems to get there. So I would say: don't. :)