There was a deal that was made a deal that was make his rule possible. She was the missing piece and they handed it over to her. Who would have thought that the love the parent had for their child were so small that the sold her soul to the pit of nothing just for a slim chance of freedom.
The tides of evil has been shifted and his rule will be absolute with something so precious to the one that he wants dead he has the power of a new vessel though they won't touch it yet until the time is right.
Now all he has to do is watch and see how the outcome will end and smile from his archived victory.
Or so he thought underestimating the power of love.