First strike Whenever a creature dealt damage by Abattoir Ghoul this turn dies, you gain life equal to that creature's toughness.
Death took his humanity but not his skill with the knife.
Official Rulings for Abattoir Ghoul
9/22/2011 : You'll gain life equal to the creature's last known toughness before it died. For example, if Abattoir Ghoul deals 3 first-strike damage to a 7/7 creature and then you give the creature -5/-5 before the regular combat damage step, you'll gain 2 life.