If Edmund walked into Narnia for the first time and did not go back with Lucy, but stayed, the witch used the prophecy itself to break the prophecy and make him a unique king.
Time in Narnia is not consistent with reality. When the three Peter brothers finally found their brother who had been missing for a week in a foreign country, Edmond had already spent twenty years in Narnia as the Lonely King.
Sequels, including Part 2 and Part 3, CP Caspian/Edmund No Difference:
Intention:
