They are not children of Eli and Edna it was said in the last chapter of light and shadow (correct me if I'm wrong) that they had 3 kids, two of whom were boys as the youngest was a girl. Going by Alex's age in one of the panels in the chapter, he looks about 4-6 years old while the youngest looks about 0-1 yrs old. At present, I'd say Alex is 18-20 years old so she would be 13-15 yrs old. The nieces, on the other hand, look about Alex's age.
Also, like someone said adna and Eli have 3 kids. 2 boys and a girl. Alex, his brother Kai and his sister Alissa.
This is Trilogy, the first book is on adna and Eli, second is on their son Alex and the last book is on their daughter Alissa. also from what I read the ml in the last one is kian son.
And that’s all. I hope that the last book will get picked up too.
You might be confused. Although they might actually be nieces of the queen on her side of the family, idk seeing as I haven’t read this in awhile. But calling someone “auntie” also doesn’t necessarily mean that they’re actually your aunt. I’ve had to call my parent’s friends aunt and uncle before.
And I’ve seen other stories where a kid calls their friend’s mother “auntie” to make it less formal. Ngl I do feel like calling someone else’s parent by their name awkward for me

So if those girls are the nieces of Katrina, they must be the daughters of Edna...
Unfortunately they take after Cayden more then their father in appearance