[quote=Major Ursa]
There isn't much to say about the trio, except that they're the 'Day' 'Sun' and 'Night' personified as three riders (possibly arrant knights). They were just background characters, so they were never fleshed out. Should I tie them to other fairytale?
[/quote]

I somehow missed this...

Yes! If you can find a way to tie it into a better known story I say go for it!