Sven - Shadowhunter

Flying, ward {2}
Whenever Sven - Shadowhunter 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.