The brothers of light and shadow.
No one can tell who is whose light, and who is willing to be whose shadow.
One is God's beloved, even his heart is clear and transparent, but the other is a descendant from hell, and seems to have mastered all seven deadly sins.
The two people are so different, but they are related by blood. No one would believe it.
They are born from the same root, so there is no need to rush into mutual conflict.
The struggle between day and night lasted for a hundred days.