No life is gained.
The second part of Devour Flesh's effect refers to a creature that's defined in the first part. Because Sigarda prevents Andrew from sacrifing creatures to effects controlled by an opponent, there is no legal choice of creature to sacrifice. Consequently, the creature is undefined in the second part, so no life is gained.
Compare with Mercy Killing. There, the second part also refers to “that creature”, but this time we are talking about the targeted creature. Even if the creature ends up not being sacrificed due to Sigarda, it is well-defined and can be referred to by the second part, and there tokens are created based on the creature's power.
Daniel Kitachewsky
L3, Paris, France
Rules NetRep
Edited Daniel Kitachewsky (April 9, 2013 04:19:15 AM)