Selling a card removes it from your collection, in every save, for good. You get Skyth for it, and you can never sell your last card.
Part of eachEach save (, the world it was played in, and where you stood) included, is kept with your account, so it carries on on any device you sign in the on. The browser you played on rather than with us. Clearing play in keeps a copy too, so the game doesn't wait on the network; clearing that browser's data for the site clears itonly that copy.
Unchanged
Worked out word by word from the two versions. If the Terms of Service and this page ever differ, the Terms of Service applies.