Guin Saga 4: Prisoner of the Lagon is written by Kaoru Kurimoto.

Though decimating the vaunted Red Kights of the Mongauli Army in a sea of deadly yidoh, the combined tribes of the Sem remain vastly outnumbered. Guin decides to leave his friends in search of the legendary Lagon. He must find the giant warriors before the fragile Sem alliance unravels and the tribes fall to the Mongauli. Meanwhile, Istavan, the mercenary's deft covert-op, helps destroy the Blue Knights.