Rilian

Rilian was the son of legendary King Caspian X of Narnia, fated to become king himself. (He was apparently born in Narnian year 2325, however, his reign, in year 2356, was supposed to be over 200 years before that of King Trinian which was much less than 200 years later, leaving some debate as to the correct years of such events.)

As a young man, Rilian's mother was attacked during a nap in the northern lands and killed by a Great Serpent and from then on, he always returned to that place, hoping to avenge his mother's death.

However, Rilian, once up in these northern lands himself disappeared and as many knights as his father Caspian sent looking for him, they all vanished as well. Legend of the Great Serpent in fact being a Witch-queen spread and Eustace Scrubb and Jill Pole were transported into the Narnian realm to rescue the lost Prince Rilian.

When they found the entrance to Underland, a subterranean country, below the Ruined City of the Giants, Eustace and Jill, with their companion, the Marsh-wiggle Puddleglum, were confronted by an arrogant knight who claimed his queen would make him king of a country and they would be married. However, it was said the knight transformed into a Great Serpent each night and so was tied up to a magical, silver chair to restrain him from being loose in the form of the deadly snake. Upon witnessing the beginning of the transformation, Puddleglum, Eustace, and Jill all realized the knight was in fact under a spell which manipulated him, the enchantment re-conjured each night that he was sat on the silver chair. Just before his transfiguration, the three cut him loose and the knight was turned back to his normal self who was really the lost Prince Rilian all along.

Now in a normal state, Rilian and the others encountered the With-Queen of Underland herself who at first tried to charm them but then turned into the terrible Great Serpent and attacked Rilian. Eustace and Puddleglum decapitated her and liberated the Underland gnome-slaves who were also under magical control which made them do tireless work without revolting.

The four heroes, including Rilian (apparently 31 years old at the time), made their way up to the surface which was surprisingly on the grounds of the country Narnia where Rilian's old father died within the next few hours leaving Rilian to become Narnia's next ruler.

Although it is known Rilian had a successful regime, certain dates and facts (some from The Last Battle) give reasons that seem to state Rilian's reign lasted exactly "negative one" year, which of course is impossible.