Since I don't know the exact 'the hanged king story', the main characters could include the hanged king himself, of course. There might also be his executioners, and perhaps his family members like a queen or a prince who would be affected by his death.
The main characters in the 'the hanged king story' are likely to be the hanged king. Then there could be his advisors, some of whom might have betrayed him leading to his hanging. There could be a group of rebels who instigated the events that led to the king's death. And also, there might be a priest or a religious figure who had some influence on the situation, either supporting or opposing the king's rule, which ultimately had a bearing on his fate.
In the 'the hanged king story', the king is the central figure. But there could be other important characters too. For example, a court jester who was close to the king and witnessed his downfall. There may also be a powerful wizard or sorcerer who either played a role in the king's hanging or tried to prevent it. Additionally, the king's loyal knights who might have tried to save him from his fate could also be main characters.