I am looking for a book/series written in the 1980's about twin boys. One is stolen at birth by evil monster demons and is raised by them to be evil. I believe I remember that the land in this book is divided by a line where one side is always night and is where all the evil lives. I think these twins had magic and are the children of the king. Can anyone help me? I can't remember the author or the title. I never got read the next book in the series and would love to find it again.
Could it be the War of Light and Shadows by Janny Wurts?
Born on a splinter world, Lysaer and Arithon are half-brothers raised apart in enmity. Cast through a Worldsend Gate, they arrive in Athera, the ancient world of their ancestors cloaked in the fog of the malicious Mistwraith.
Only the combined powers of two half-brothers can challenge the Mistwraith’s stranglehold: Arithon, Master of Shadow and Lysaer, Lord of Light.