Specter of Unspoken Debts

(If {w/b} was payed with {w}, this creature is white
and black.)
When Specter of Unspoken Debts enters, if
it's white, target opponent loses half X life,
rounded up, and you gain half X life where
X is your devotion to black.
As long as Specter of Unspoken Debts isn't
white, it gets +1/+1 and gains flying and lifelink.