Akuma:

Something called an Apathy, he is the Mind of someone who has been consumed by Light, though he is incomplete because of how he was created. He wants to save all Apathies from servitude to their Calamitous. Castus' Apathy.
He remembers nothing of his past, the memories go the Nobody, but he does have the most accurate way of behaving and posesses all the knowledge the original person posessed.
His hair is balck (dyed), tipped silver (natural), and he has red eyes, like all Apathies.