King Arthur is a central figure in the story about the Holy Grail. His knights are also key. Sir Lancelot is a well - known knight, but his relationship with Guinevere causes some complications. Sir Galahad is a pure knight who has a special connection to the Grail. Sir Percival is another important knight on the Grail quest. And Merlin, with his magic and wisdom, guides and influences the events related to Arthur and the search for the Holy Grail.
The main characters are King Arthur himself, of course. Then there are his knights like Sir Lancelot, Sir Galahad, and Sir Percival. Merlin, the wizard, also plays an important role in the story related to Arthur and the Holy Grail.