Talk:Formal Craft/@comment-181.93.194.90-20170719063414/@comment-4802891-20170719063740

Because it's a 5-star cards, they are locked by default when you summon them. Tap and hold on the copy you want to feed to the main card to see its profile, then unlock it by tapping the "Lock" symbol on the left of the picture. Go back and proceed with the rest.

Be careful that if the card you want to feed is already on another Servant in any kind of situation, you won't be able to feed it either.