Fretia, The White Priestess

Hexproof
When you cast this card create Umbral Knight a legendary 4/5 black Spirit token with vigilance
Whenever a Transformed creature dies,
add it to your hand,
then place a impure counter on this card
At the beginning of your upkeep, if this card has
6 or more impure counters, transform it.
{t} You gain 3 life.