Template:Infobox Item Mysterious gem are items used for training mysterious cards and unlocking mysterious card side stories. To train a 3☆ card, 100 mysterious gems are needed. To train a 4☆ card, 200 mysterious gems are needed. To unlock the second side story of a 3☆ card, 600 mysterious gems are needed. To train the second side story of a 4☆ card, 1200 mysterious gems are needed.