I don't think it's about Christ or Satan. I think it's written from the point of view of an unfaithful party of a relationship.
This is my interpretation:
Valo, or whomever he's taking the role of, has cheated on his partner (this is shown in the lines about his heart bearing shame, and the countless mistakes).
And now in the song, he's proclaiming his love for her, possibly wanting forgiveness, even though it's useless, because trust has "faded away."
I don't think it's about Christ or Satan. I think it's written from the point of view of an unfaithful party of a relationship.
This is my interpretation: Valo, or whomever he's taking the role of, has cheated on his partner (this is shown in the lines about his heart bearing shame, and the countless mistakes). And now in the song, he's proclaiming his love for her, possibly wanting forgiveness, even though it's useless, because trust has "faded away."