Kather, Profound Mender

Hexproof from Phyrexians
Hexproof from Compleated sources.
Kather can't have her power increased.
Whenever Kather blocks, she gains +0/+X
while X is the blocked creature's power.
That remain until she becomes tapped.
{w}{w}{t}: Gain X life.
You may prevent up to X damage
that would be dealt to target creature or Planeswalker this turn.