In the year 840 AD a great king, then only 16, took the throne of England when he drew the sword Excalibur from the anvil and stone (see section on Excalibur for details). He grew up to be just and wise, much due to the teachings of the great, but demented, Mrrlyn. He grew up in the traditions of the great knights and firmly believed in the honorable ideals of the round table.
Many legends of Arthur are true, many exaggerated, many complete fabrications (like much of T. H. White’s The Once and Future King.)
The Nog Henge Druids as described in Rifts England have been mankind’s protectors long before Rifts. Even before the days of Arthur, these Chiang-Ku were formulating a plan to save mankind from itself. This was achieved through a Spirit of Good named Glorina. She taught the Chiang-Ku the art of Temporal Wizardry, established a haven for them in Avalon (discussed later- see below) and is helping to remove Mrrlyn’s influence over Arthur. The Nog Henge have developed a complicated plan that will plant Arthur’s ideals of peace and harmony in the hearts of all good peoples. Those such as the Splugorth who will reject peace will be expelled from Earth forever. The plan will be outlined later (time travel is hard to follow and needs its own section.)
*Note: none of these legends were EXACTLY correct, and are discussed below.
To begin with, in the traditional tale of Excalibur, it was received from the Lady of the Lake. This is not accurate, for it was truly the sheath of the sword that was held by the Lady. Excalibur itself was drawn from the stone on Easter of 840 AD.
Excalibur was a gift to Arthur (unbeknownst to him) by the Goddess of Light named Glorina, and the Nog Henge Druids. The Nog Henge, possibly the most Scrupulous institution in history, asked Glorina for help in establishing a kingdom for mankind, one which would help to fight the ever-growing evil presence on Earth. Excalibur is an extenuation of Glorina held by a powerful Rune weapon that she herself created... it is a fragmented essence much like Mrrlyn. This allowed her to keep watch over who was to be mankind’s mortal savior from Evil. The powers of Excalibur are those of Glorina, and she gives them at her discretion. This is sometimes in answer to a subconscious request for help by Arthur or the occasional "miracle" (i.e. a force field blocking what would have been a fatal blow).
The sheath of Excalibur is a magic object created by Glorina, which bestows upon the user the super abilities of Invulnerability and Extraordinary Physical Prowess. Unlike the sword, the sheath can be used by anyone holding it. Mordred wore it in the battle upon the fields near Stonehenge. Glorina, being the 4th dimensional being that she is, knew of this development beforehand, but was not concerned because she knew that Arthur would live through this necessary ordeal. Only someone using Excalibur can do significant damage to someone holding the sheath.
This is somewhat of a grueling tale, but one that needs telling. Morgana, a which linked to Zazshan and also Arthur's half sister, had a ribbon of human skin that she tied around Arthur's head while he was sleeping. It enchanted him and she conceived a child, Mordred, by him. This was part of a contingency plan, created by Mrrlyn, to kill or further control Arthur should it become necessary.
When Arthur found out about the child, he gathered all newborn babies in the kingdom and set them adrift on a raft, hoping to kill them and save his political livelihood. This is where Glorina steps in directly for one of the first times. Glorina would not allow her hero to kill these children, even if Mordred were one of them. Glorina had no fear that Mordred would kill Arthur, so she directed him back into the arms of his mother, who raised him to hate Arthur. Though part of Mrrlyn's plan, it was also incorporated into Glorina's that Mordred "kill" Arthur.
The Holy Grail, that blessed chalice used by Jesus at the Last Supper is one of the Megaverse's most powerful and mysterious items. Glorina herself knows little about it, other that it was created by a force more powerful than her (which is saying a lot) or any of the gods of the Pantheon. (Hmmm…) It was necessary or the Nog Henge to recover the Grail to aid Arthur in his passing into Avalon. The Chiang-Ku needed the help of certain Knights of the Round Table because the Grail can only be accessed by mortal (non-supernatural) hands.
The actual quest is for you to flesh out as you choose, but I'll give you Galahad's basic story. (It is important to note that this is NOT the Galahad from Rifts England). Galahad, son of Lancelot and Elaine, grew up in training to become the world's greatest knight. Raised in a nunnery, Galahad was a virgin and a vegetarian and was completely without sin. He embarked on the quest for the Holy Grail at the age of eighteen and surpassed many a great knight in contest, even the mighty Lancelot. Galahad was blessed, having a sort of intuition on certain matters, and was considered a saint by most people. A nun (a Chiang-Ku, also the lady of which Lancelot speaks in the quote below) led him to a magic barge. He there joined Sir Bors (6th level knight, 2nd level priest) and Sir Prrcyvel (yes, the same one as in Rifts England, transported as a representative from the Nog Henge to help Galahad and Bors find the Grail.)
The following is an excerpt from T. H. White's The Once and Future King and serves as a reference to the Nog Henge's involvement in the Arthurian legends. Remember that there are 11 members of the Nog Henge.
"Galahad was inside, and Bors, and Percivale. There were nine other knights, from France and Danemark and Ireland: and the lady from my ship was there as well. The Grail was there, Arthur, on a silver table, and other things!"
Sir Lancelot, relating his tale to King Arthur and Queen Guinevere
The nine knights, the lady and Percivale (Prrcyvel) are the Chiang-Ku of the Nog Henge. Also present were Galahad, Bors, and a priest who was conducting Mass. They were allowed entrance due to their spiritual nature and the special role they played as ally's in the Nog Henge plan.
These are worth mentioning, but not worth going into. It is enough to say that it happened and nearly drove the king mad when he found them together. Guinevere later joined a nunnery and kept Excalibur until Arthur left to fight Mordred. It was then that it was returned to him.
Lancelot was a principled knight and all of his dealings with Guinevere were the result of Mrrlyn's magic and psychic influence over them both. Neither would have ever betrayed Arthur otherwise.
Avalon is another dimension in which time has no meaning. It is basically a null-time zone (a la Transdimensional). Time seems to pass inside Avalon to some extent (sun comes up and sets like it would anywhere else... a roughly 20 hour day), but has no relevance to the outside dimensions. No one ever ages and no one can be conceived or born. People can still live and breathe (it is not a stasis-like environment). However, no one can ever die in Avalon. The PPE environment is so rich that wounds heal at 10x the normal rate. Poisons and curses are automatically negated upon entering Avalon, and any possessing entity is automatically expelled. Avalon is invaluable to the plan of the Nog Henge Druids and Glorina, because from there (or any Null Time Zone) you can access any day, year, second, century, etc. in the past, present, or future. It is here that Arthur was taken by the three strange women described in many of the legends, including The Once and Future King. These "women" were actually Nog Henge Chiang Ku, one of which was the young Prrcyvel, the other two were actually the same Dragon named Shol Ra (one was from the future, returned to teach young Shol about time travel. Besides, when the older one was young, HIS older self had been there as well, so he had to fulfill the past. Time travel is touchy, paradoxical stuff.) Arthur was taken to Avalon and given drink from the Holy Grail, which instantly cured his wounds and avoided the brain damage that he would have suffered from his wound. He then began training, learning, and preparing for his coming in glory.