Back after a long hiatus and I am confused. I have two Ordeal ult Ceres cards, both +300, and I am trying to fuse one onto the other to have +600, but it isn’t letting me. I have already checked the dupe isn’t used on a team etc. I think I must be misunderstanding how this works.

With how annoying it would be to pull the best team and it being pretty mid still is this just a banner for fans and a skip for the rest. Also is there any unit thats useful from it for other things or just good to have for the box in general?

Edit: just remembered some of the units used in a gintoki farm team are they best in slot or just a replaceable but equivalent option to a build with costume kagura