Allen always wondered what it felt like to have his soul eaten alive by a demon.
Throughout his whole career as an exorcist he brought salvation to Akuma, freeing them from the evil clutches of grief and sorrow, rescuing the mourning souls and the spirits brought back from the afterlife. He heard the screams of terror in their hearts. He saw the tears of sorrow. He could feel their pain as if it were a parasite that seeped through his skin and crawled through his veins.
The power of the demon was as real to him as any flesh wound. He suffered through the pain of loss himself through Mana's death.
But oddly enough, he could not remember how it felt to be destroyed from within. Maybe because the Millenium Earl never had a chance to cut him open for the demonized Mana to access his body and soul, Allen never truly faced the wrath of the demon.
But to think he could just forget how much pain he endured. Did the human mind have such a powerful capability to purge torment? To release suffering that no longer served a purpose for him?
As his Innocence purged the evil from the Akuma, Allen always looked at the rising souls with interest.
What did it feel like to have his soul eaten alive by a demon? He will never know.