Items from the tool belt are not listed unless they do not work or are not automatically added.
At least 120 coins to travel to Brimhaven and back twice unless wearing the Ring of charos(a) or using a different transportation method (if you want to use charter ships instead, bring about 3,200 coins)
Speak to King Arthur and he will tell you about the Holy Grail, and tell you to ask Merlin about it.
Speak to Merlin, located on the second floor of King Arthur's castle.
Now you are going to Entrana, so don't take any weapons or armour, including your explorer's ring (there is a bank deposit box on the dock in Port Sarim where you can deposit forbidden items). To get to Entrana take the boat from Port Sarim. Alternative methods include traveling via hot air balloon, using the Abyss to access the Law Altar, walking from there, or, if you have level 50 Runecrafting, purchasing a Law Teleport tablet will work similarly.
Speak to the high priest of the church. He will say the Holy Grail is no longer here. Then a strange old Crone will appear and say that Fisher King is in trouble, and that you will need to find 6 Mysterious statues around the world and go to where they point when you have a Magic whistle. However, you don't necessarily have to find any of the Mysterious statues to proceed.
Helping the Fisher King
Go to Galahad and talk to him (he's in a building west of McGrubor's Wood). Tell him you're on a quest for the Holy Grail. Then, ask him why he left the Fisher Realm and he will give you the Holy table napkin.
Now head to the top floor of Draynor Manor and go into the southern room. You need to have the Holy table napkin with you, or you won't be able to see the whistle. Pick up two magic whistles. They will not be visible until the player walks into the room. Now head to the nearest bank and gather food and items you might need to fight the Black Knight Titan. Go to Brimhaven, (Faster way is by charter or Amulet of Glory) and blow the whistle in the location shown in the picture.
There is a battle approaching, so prepare yourself. Have the magic whistle, Excalibur, a weapon, armour, and some food with you. Head to where the 6 stone faces point, which is on the north-west part of Brimhaven and north of the gold mine, where a tower is standing. Go under the tower and blow the whistle and you will be teleported to the Fisher King's Realm.
To speak to the Fisher King. The Black Knight Titan stands there and won't let you through without a match. The Titan can hit up to 150 so be prepared. If possible, use the Protect from Melee prayer. He is almost impossible to hit using ranged combat, although you can use magic for the majority of the battle if you wish. Take him down to low life, and then wield Excalibur to finish him off. If you don't use Excalibur for the final blow, then you must face him again. He doesn't move, so you can walk away at low health to eat without being damaged. If you happen to lose the battle and run away, when you come back he will still be damaged. You can Halberd him, which makes the fight very easy, as he will be unable to hit you. However, you MUST remember to switch to Exalibur when he's at low health. An alternative method to fighting him without food or prayer is hitting him and running back a few squares before he can strike you. A player can avoid getting hit even once if they are fast enough. Do note that if you are attacking with a poisoned weapon, only the first poison damage will be dealt, subsequent poison damage will not be dealt if you run away.
After you have killed him, cross the bridge and head to the fisherman by the river and talk to him. Ask the fisherman how to get into the castle - or you will not find the bell.
Now head up the hill to the castle and take a Grail bell. Ring it and you will be inside the castle.
If you didn't get a spare whistle while in the Draynor Manor, do so now. There is one on the floor of the castle and one on a table on the first floor. You need to have one for you and one for later.
Head upstairs and speak to the Fisher King. He is very sick and wishes to see his son once more. The son's name is Percival and he is a knight of the round table. Now blow your whistle again to be teleported out. If you do not ask him about his son, you'll have to do it all over again!
From now on, you no longer need food and armour, so put them in bank to save running energy.
Blow on the feather and it will guide you towards Goblin Village. Go there now.
Once there, head into the east house, open the sacks and you will find Sir Percival. Tell him his father wishes to see him. Percival doesn't know how to get to the castle so give him the second magic whistle. (Note: If you do not have a Magic gold feather in your inventory when you try to open the sacks you will receive a message saying "I have no reason to do this" and will need to get another from King Arthur)
Now you must head back to the Fisher King's Realm once more. You can do this by blowing the whistle under the tower, north-west of Brimhaven (you don't need to fight Black Knight Titan this time). If you have access to the fairy rings you may also get there by dialling BJR.
Once in the Fisher King's Realm, head to the castle, and go up the stairs. Now head to where the Fisher King should have been, and you find Percival as a king, and the land restored.
Head back downstairs and go up the staircase on the other side of the castle and climb all the way up. Now you can take the Holy grail. Now blow your whistle and head back to Camelot.
Bring the grail to King Arthur. Congratulations, quest completed!
The Black Knight Titan is based off a major character in the original King Arthur legends.
You can attempt to fight the Black Knight Titan again after the first time you defeat him, but you will pass back across the bridge.
The Grail Bell is the same image as the servants image on the construction guide.
You can say, "I seek the Holy Grail" to The Fisher King. This was said by King Arthur in the film Monty Python and the Holy Grail, another reference to this film may be to the black knight titan and the armless and legless black knight defeated in the film. Of corse, the Monty Python film was based off the original legends of king Arthur, consequently, all references to other parodies come back to them.
If you attempt to take a second grail, you receive the message "You feel that taking more than one Holy Grail might be greedy".
After saving Percival, the sack can be prodded and still grunts.
Upon completing this quest, a Player's Adventurer's Log will read: "I defeated the Black Knight Titan and restored peace and happiness to the Fisher King's kingdom. I also found the Holy Grail."
The appearance of the Black Knight Titan is similar to that of serial killer Michael Myers from the "Halloween" series.
After completing the quest, if you talk to Juna, your character will say, "...And out of all the knights of the Round Table, it was I who found the Holy Grail."
When talking to the Black knight titan you have the option to say "Actually I think I'll run away!" this might be a reference to Monty Python and the Holy Grail.
Many players of higher levels (100+) train on the Black Knight Titan because regardless of how they fight it, it will never die unless hit by a blow from the sword Excalibur. Please note that the experience given by these hits is very low as Jagex has nerfed it to prevent exploits.