There are 5 books in the Witch World: High Hallack Cycle series. The newest book is Gryphon's Eyrie which came out in 1984.

1
The Jargoon Pard

The Jargoon Pard
A young heir is drawn into a labyrinth of deception, death, and magical destiny in this bold adventure in the bestselling Witch World series.
 
Kethan is heir to the throne of Car Do Prawn in the realm of Arvon—but there is little he has to be proud of. He can…
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4
Gryphon in Glory

Gryphon in Glory
As Joisan sets out from her Dale refuge in search of her wedded lord Kerovan, strange forms of the Dark awaken and the Hounds of Alizon, invaders from overseas, threaten to overrun the Dales

5
Gryphon's Eyrie

Gryphon's Eyrie
Recounts the struggle of Kerovan of Ulmsdale, child of the Dark and the Light, and Josian, who loves him, to understand and master the powers within them and by so doing save the world