Krig, the face of the dead

Changeling
Whenever an opponent cast his or her first spell
each turn, that player flips a coin.
Tails = mill X cards / Heads = lose X life.
Where X is the converted mana cost of that spell.
{b}{u/r}: Krig becomes a copy of any creature
card in a graveyard until end of turn.
At the beginning of your upkeep, if there are no
creatures cards in all graveyards, you lose X life,
where X is the number of creatures on the battefield under your opponents control.