Hill suddenly felt that Graciela was indeed Asmodeus's greatest retribution.
This girl, even when scheming and plotting, managed to select a role as intriguing as 'Aislin'... He now somewhat suspects that the true character behind that virtual mask is the girl full of trust and reverence for Ruth, possibly a blank soul she uses to fill the void in her own incomplete soul shard.
It might even be possible that those blank souls merged their entire will to form a real soul.
If it were any other great devil, even if they did the same things as Graciela, the result would not be the same... It's not that easy to gather so many powerful souls.
Including Graciela's former husband, the mighty Duke Mamon of Minos in the Third Hell, whom even Asmodeus could not kill directly, didn't have this ability.
Otherwise, pure and powerful souls wouldn't be precious enough to warrant a great devil spending over ten thousand years waiting.
