2014-07-18 : Exiling the Soul from your graveyard is part of the last ability’s activation cost. A player can’t remove the Soul in response to prevent you from activating the ability.

2014-07-18 : To determine how many cards to draw, count the number of colors among permanents you control as either activated ability resolves. You’ll draw between zero and five cards.

2014-07-18 : You can activate the last ability only if the Soul is in your graveyard.