Rilian

Rilian is introduced in The Silver Chair as the only son of the elderly King Caspian and grandson of Ramandu the star. Ten years prior to the narrative he disappeared after repeatedly visiting the place where his mother was killed by a green serpent; he had been captured and enchanted by the Lady of the Green Kirtle and held underground in the Shallow Lands until rescued by searching companions.

Under enchantment he is presented to rescuers as a 'knight in black armour' bound nightly to a silver chair; in the BBC (1990) television adaptation this guise includes a silver mask used to conceal his identity. After the enchantment is broken he is recognizable as Prince Rilian, described as the son of King Caspian and grandson of Ramandu.

Rilian is a human prince and not described as an independent supernatural being. Narratively he is susceptible to external enchantment and control by the Lady of the Green Kirtle, who enforces a nightly binding to a silver chair and imposes a false knightly persona. When freed he demonstrates martial skill and agency: he breaks the enchanted chair with his sword and helps slay the green serpent that was the Lady's true form. Claims made while he is enchanted (that he will 'turn into a deadly green serpent' or kill those nearby) function within the story as threats tied to the enchantment rather than independently documented metamorphic powers of Rilian himself.