Lady Trishna, the Embersworn

Flying, prowess
At the beginning of your upkeep, you may exile
a non vampire creature card from a graveyard. If
you do, add {x}, where X is the exiled creature's
mana value. Until end of turn, you don't lose
this mana as steps and phases end.
{3}{b}: Target opponent loses life equal to the
number of cards they own in exile.