Golden Trillium by Andre Norton (1993, Hardcover, Illustrated)

Read much of this series as a teen when they came out.

This book well written and interesting and focuses on the adventures of Kadiya, the middle sister, after the defeat of Orogastus by the three sisters.

Don't read this imagining it to make sense in the context of Blood Trillium or Lady of the Trillium, though- this is like an alternate storyline for the second book in the series (after Black Trillium). In this version of the storyline, Orogastus is defeated for good at the end of Black Trillium (which is not the case in the Blood Trillium- Sky Trillium books).

A bit confusing if, like me, you decide to read them all one after another...