Redeeming Knight

Whenever a creature is killed by RK increase its Justice by one.
( RK has {x} amount of {w} symbols in it's converted mana cost, {x} being equal to its Justice )All black creatures get -{x} -{x} equal to RK Justice count. RK can not be killed, put to a graveyard, removed from the battlefield by a black source.
RK's takes double damage from white sources
Darkness within - At the start of a phase if this creature has 0 or less Attack deal damage to all non-black creatures equal to its Justice.