Rainbow Dark Dragon [BLRR-EN054] Ultra Rare

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