«Android at Arms» by Andre Norton

When Andas Kastor awakens in an alien land, he must figure out if he’s the true emperor of his home world or an evil doubleIn a stark, arid wasteland, a man awakens from a frozen state. As he stares out his narrow slit of a window, he has no memory of how he got there—or why. All he knows is his name: Andas Kastor, Imperial Prince of Inyanga. But instead of the luxurious trappings of his royal palace, he’s in a hellish, storm-lashed place punctuated by howling winds and shattering streaks of lightning. And he’s not alone.In this uninhabited world, he meets five other survivors, also of noble birth. They include the scaled, emerald-haired Elys of Posedonia and clawed, fanged Lord Yolyos of Sargol. They all speak the same Basic language, as befits those from neighboring spheres. Were they abducted, spirited to this alien planet, and held in mind-lock while evil doppelgangers ruled in their places? After a daring escape, Andas returns to Inyanga—only to discover that decades have passed and another sits on his throne. Now, hunted across barriers of time, Andas must fight external and internal enemies to save his civilization and uncover the truth about his identity.