Whenever a nontoken creature enters, its controller creates a token that's a copy of that creature.
Whenever a nontoken creature leaves the battlefield, exile all tokens with the same name as that creature.
When Dual Nature leaves the battlefield, exile all tokens created with Dual Nature.
Whenever a creature card comes into play, its controller puts a creature token into play that's a copy of that creature.
Whenever a creature card leaves play, remove all tokens with the same name as that creature from the game.
When Dual Nature leaves play, remove all tokens created with it from the game.
--This card has no flavor text --