Shadowheart, Shar Devotee

Defender
{w/b}{w/b}{t}: Add 2 Shadow Counters to Shadowheart,
Shar Devotee, and remove 1 toughness
{w}{b}: Transform Shadowheart, Shar Devotee into
Shar The Dark Sister with X loyalty, where X
equals how many shadow counters are on Shadowheart,
Shar Devotee. You may do this as a sorcery