The blessing of the fountain of life turned into a curse on the Warrogs because the original Warrogs had their own divine ability which wasn't compatible with the law fragments of life. The fountain of life had to curse the Warrogs because even with the blessings, the tree people were of no match to them.
So the will of the plane chose a Warrog as a good champion and the demon God also wants his own champion. The future Executioner will do nicely for that position of honor.
The demon God of Carnage was aware of the existence of the Emperor but it couldn't find her. It had no hopes of finding the Executioner even though it sent out vampires to attack the surface of the plane. So this is a lucky encounter for the demon God.
It is good news but the situation also made the demon God very frustrated.
CARNAGE complained, "What do I do now? How do I get him? This is so frustrating. I shouldn't have promised that Xigger anything."