Initially I though need to collect 4 pieces of map fragments to get this sweet treasure chest so i used copy cat ability to make 2 more copies of map fragment and wish to encounter the 4th fragment. I didnt dare to use those fragment bcoz they only charge 1 and i though they will disappear like the strange stone. Maybe you should write the instruction clearer like "use it 4 times" instead of "collect 4 ..." Overall this is a great game with high replayability. Well done.
PS: I wish i can remove unwanted passive ability like hearty and view all items card available in the card library.