Rainbow Dark Dragon [BLRR-EN054] Ultra Rare

(This card is always treated as an "Ultimate Crystal" card.)
Cannot be Normal Summoned or Set. Must be Special Summoned (from your hand) by banishing 7 DARK monsters with different names from your Graveyard, and cannot be Special Summoned by other ways. You can banish all other DARK monsters you control and from your Graveyard; this card gains 500 ATK for each card banished this way.