Which fictional literary character is also known as the "Guardian of the Eastern Dark?"

Lee Falk worked on The Phantom until his death in 1999; from then until the present, the comic strip has been written by various writers and artist. In the strip, the Phantom was 21st in a line of crime-fighters which began in 1536, when the father of British sailor Christopher Walker was killed during a pirate attack. Swearing an oath on the skull of his father's murderer to fight evil, Christopher began a legacy of the Phantom which would pass from father to son. Nicknames for the Phantom include "The Ghost Who Walks", "Guardian of the Eastern Dark" and "The Man Who Cannot Die".

Unlike other fictional costumed heroes, the Phantom relies on his strength, intelligence and reputed immortality to defeat his foes. The 21st Phantom is married to Diana Palmer; they met while he studied in the United States and have two children, Kit and Heloise. He has a trained wolf, Devil, and a horse named Hero. Like the previous Phantoms, he lives in the ancient Skull Cave.