Marriage of Opposites

Whenever you cast a white spell, you lose 1 life
and draw a card.
Whenever you cast a black spell, you gain 1 life
and draw a card.
At the beginning of your end step, if you gained
life this turn, create a 1/1 white Bird creature
token with flying. Then, if you lost life this turn, create a 1/1 black Bat creature token with flying.