[The creator dislikes the old name of the au so we change it into something simple which is Sun & Moon]
Palette represent the 'Sun'. Sun can be seen as a perfect light of the world but at the same time very lonely because literally no one love sun like they love moon.
Lux represent the 'Moon'. The sickly beautiful god's creation. Of course, everyone love moon more than sun. Even if the moon did something bad, they still prefer moon over sun.
[A/N: this is creator Lily speaking. I made a mistake by drawing Palette white skinned in this picture. Palette is supposed canonly tan/black in here.]