Sunset and Twilight's relationship takes place after sunset returns to equestria in my universe (sunset also becomes princess later~), I'll talk more about it when I post more drawings of them
but anyway, later on, they had three children! they are (from top to bottom);
Glowing dusk:
Glowing is the youngest daughter of Sunset and Twilight, she is the heir to the throne even by age, in the order of equestrian succession being matriarchal. Like Twilight, she is neurotic and is often anxious, mainly because she can't deal with her future as a leader. It resides in the castle of friendship. Dedicated to the study of stars, portals and spells
Glooming Nightfall:
The middle child, he is ambitious and uses dark spells, just like Sunset was before. He lives in Canterlot and is not very close to his family has a slight abandonment complex. He's punk/goth (I was inspired by the clothes sunset wears in equestria girls). Study demonology!
Daydream Glow:
The eldest son, a mage who studies about the magic mirrors that lead to different dimensions, able to keep them functional if they needed to be used, but still locked away to avoid unwanted visitors and time paradoxes, just like the equestria girls mirror
He lives in the Crystal Empire and is very close to his uncle Sunburst and cousin Flurry Heart.