From my research, i've found that this image depicts Percival meeting the Fisher King. Percival, however, is wearing red armor, something we've never seen him in before. Thus, the story of the Red Knight comes to light! Once, in Camelot, the Knights of the Round Table were meeting for the Autumn Equinox. They were celebrating, drinking, hanging out with beautiful ladies, the usual. A fair maiden brings the Queen a golden grail so she can make a toast. SUDDENLY, A Red Knight barges in, takes the grail, throws its contents on the Queen, and challenges all the knights to come fight him. One will have the chance to fight the Red Knight, and they all scramble to be the first to put on their armor. Percival, however, was already out on an prior quest, and returned right when the Red Knight was leaving. He and the Knight duel, leaving the Red Knight wounded and fleeing into the forest. Percival pursues, and comes across a Red Castle. Upon entering, he sees the Red Knight sprawled on the altar with his wound exposed. A women enters with the grail, and Percival is so stunned he cannot speak. Suddenly, the one candle in the WHOLE CHURCH blows out and Percival's horses freaks out, flees, and causes Percival to flee the church to pursue his horse. Upon recapturing, he can no longer find the Red Church, similar to how the Fisher King's castle was magical and can only be seen by those who need to see it. He goes into town, and comes across his Aunt who agrees to teach him combat and British history. She teaches him that the woman was a Maiden of Wells, and that she was his sister, Dindrane. He learns that the golden chalice was sent to Camelot to find who was worthy of taking the place of the Red Knight as Guardian of the Red Chapel because he was growing too old. By inquiring about the grail, Percival had already passed the first test and could begin training as a Chaplain. He goes back to the Red Chapel, finds the Red Knight healed and begins training. When the time comes, be becomes Chaplain of the Holy Grail and Guardian of the Red Chapel. He gets to wear the Red Armor of the Red Knight, which is why he is depicted here, meeting the Fisher King, in Red Armor. He still goes on occasional quests, but he always returns to the Red Chapel to fulfill his duties. This is why Percival is also the Red Knight, and how this image correlates to the the Tale of the Fisher King. Percival, here, is already Guardian/Chaplain, making him prestigious. Perhaps if he had asked the Fisher King the same questions as his Aunt, he would have saved him too, and fulfilled the quest.