Elenda and Azor

Flying, ward {2}
Whenever Elenda and Azor attacks, you
may pay {x}{w}{u}{b}. If you do, draw X cards.
At the beginning of each end step, you may
pay 4 life. If you do, create a number of 1/1 black Vampire Knight creature tokens with lifelink equal to the number of cards you've drawn this turn.