Merlin

"Many believe he was a wizard of darkness. He may have tried to do good, but there was always potential for great mischief in his heart."

- Antonius

Merlin (Merlyn, Myrddin, Merlinus) was a Lantean who created the Sangraal.

Background information
Known as Moros in Atlantis, he served as High Counselor of the Lantean Council during the War with the Wraith. When Dr. Elizabeth Weir was sent back in time 10,000 years, Moros refused to allow her to use Janus' illegal technologies to return to her time, in fear of altering the timeline. He strongly chastised Janus for conducting the experiments with time travel technologies to begin with. He gave the final order to the Lanteans to evacuate to Earth when a Wraith fleet approached Lantea.

Upon arriving at Earth, Moros secluded himself in meditation, and eventually ascended. While ascended, however, he came to the conclusion that the Ori were too great a threat to ignore. He descended himself, while retaining all his acended knowledge and granting himself many near ascension abilities. The Others, however, feared his intentions, and sent Ganos Lal to watch over him. While on Earth, he entrusted his secrets to King Arthur and some of his noble men. They came to call him Myrddin, or Merlin.

2005
Vala Mal Doran stole a tablet written in Ancient code. The tablet told of an incredible treasure hidden on Earth and the man who carved the tablet was named Myrddin. This Myrddin was found in the list of names of the Ancients who returned from Atlantis to Earth more than 10,000 years ago to escape from the Wraith. Myrddin, Dr. Daniel Jackson discovers, is a name variant of Merlin from the legend of King Arthur.

They localized where the treasure might be located, at the Glastonbury Tor and the Isle of Avalon. With help of the Asgard sensors on the Prometheus and the Ring transporter, Lt. Colonel Cameron Mitchell, Daniel, Teal'c and Vala came into a large cavern and were shortly thereafter faced with a Sword In The Stone and a holographic image of Merlin. The hologram gave his message, addressed to the Knights of the Round Table, telling them that they would have to prove they had truth of spirit and wealth of knowledge in order to obtain the treasures hidden in the underworld, the storehouse of riches of Ambrosius Aurelianus, the name attributed to King Arthur in some versions of Arthurian legend.

2006
It was several months later, that Stargate Command learned the purpose of the vault. Merlin was hiding his research on the Sangraal, the weapon designed to negate the power of an Ascended being. To hide his research from both the Ancients and the Ori, Merlin shifted himself into another dimension using Arthur's Mantle, and continued his research on Camelot. Ganos managed to steal the device, and hid it on a planet whose Stargate address was composed of three other planet's addresses: Castiana, Sahal, and Vagonbrei.

2007
Later however, it was learned that Ganos Lal had destroyed the Sangraal, and put Merlin in stasis. One thousand years later, Merlin was discovered by SG-1, who awoke him. He agreed to create another Sangraal, but his body had deteriorated too much while in stasis. Knowing that he didn't have enough time, Merlin downloaded his memories into one of the Ancients Repository of knowledge, hoping one of them would use it, which Dr. Daniel Jackson did. Thus Merlin passed, having lived four separate lifetimes—in Atlantis, on Earth, on the higher planes, and in Arthur's court—commenting that throughout his lifetimes, there had never been enough time.

However, Merlin lived on in Daniel's mind. After Daniel was captured with the Sangraal, Merlin was able to protect Daniel from Adria's influence. He and Daniel concocted a plan to send the Sangraal through the Supergate to the Ori galaxy, once SG-1 had deactivated the Supergate. Merlin sacrificed himself to give Daniel the strength to activate the Supergate. During this time Merlin's consciousness shared Daniel's body having been what was downloaded into his mind. Although Merlin had the ability to take control of Daniel's body, he mostly let Daniel remain in control while he simply used his presence to protect Daniel and re-build the weapon. He only took control once or twice to convince SG-1 of the truth. He died when the biological fail safe he installed converted Daniel back to his original state.

Later Dr. Daniel Jackson began to get dreams that pointed to the Ark of Truth that featured Merlin in them. He believed that they were memories Merlin left behind to point him to the Ark. While on a planet in the Ori home galaxy, he saw a vision of Merlin that caused him to realize they were on the right track and another vision of Merlin led him to the resting place of the Ark. Merlin appeared to him again when he was depressed from being tortured, appearing to be an Ascended Being, but this caused Daniel to realize the truth as Merlin had died and not Ascended: it was Morgan Le Fay, disguising herself as Merlin to secretly help them without them realizing it.

Behind the scenes

 * Matthew Walker previously played Roham in the Stargate SG-1 episode "Touchstone".
 * Before he was called Merlin, he was named Moros, who in Greek mythology was the god of doom and destruction.
 * Daniel Jackson's pronunciation of "Myrddin" is inaccurate. The "dd" is a single letter in the Welsh alphabet and is pronounced "th" as in "this".