Darth Taikin was a Sith (and later Jedi) who lived during the Mystic Era, a few years before the demise of Darth Noceni. His real name was unknown so he has simply been called Taikin. He was one of the few Jedi to have been a Jedi, Grey Jedi and Sith.
Early Life[]
Taikin was born on Naboo in 2200 ABY. He was found to be force sensitive, so he was taken to the Jedi Temple. He had few companions, except for a boy named Deslath Jhet, whom he was close friends with. As a youngling, he was very mischievous, getting into things he shouldn't. Once, he managed to break into the Room of Secrets, a storage room where the Jedi kept items and other things best left unseen, except by experienced Jedi. As he was exploring this vast chamber, he saw a pyramid, covered with strange markings. It was a Sith Holocron, recorded by Darth Kaligan, an artifact that Atris had found on Dantooine. He somehow managed to activate it. He learned its secrets, day by day.
Encounter[]

Darth Taikin as a Sith
Meanwhile, on Naboo, Darth Noceni was searching for an apprentice. Taikin planned to visit Naboo, so at one point he crossed paths with Noceni. After discovering that Taikin knew much about the Sith, he took Taikin to be trained as his apprentice. Taikin was willing, as the Sith Holocron had corrupted his mind. Noceni trained him for 3 years. Taikin plotted to kill Noceni, but after Darth Noceni went on a mission to Tatooine he was killed by Atris' padawan. Taikin took the title of Sith Lord.
Holocron[]
Using knowledge he found in the Holocron of Darth Kaligan, Darth Taikin managed to temporarily resurrect some of the old Sith Lords. He resurrected Darth Malak, Darth Tyranus, Darth Revan, Darth Nihilus and Darth Orcron. He was now 5 times more powerful. The Sith made an attack on Coruscant. Very few survived. It was devastating. The Jedi Council held an emergency meeting, to see what could be done. They only agreed that Darth Taikin should be stopped.
Revelation[]

Taikin's challenger
Darth Taikin went to Dantooine to kill the Jedi at the Academy. This he managed without too much difficulty. However, as he was departing, he saw a hooded figure who drew his lightsaber. Darth Taikin fought back strongly, and he soon had his lightsaber poised at his opponent's throat, when the hood was removed. It was Deslath Jhet. Darth Taikin felt himself start to lose grip on the lightsaber. Eventually, he turned away and deactivated it. Then his friend spoke. "I came to make you understand what you are doing. It appears you now do." Then he disappeared. Darth Taikin realized he had been battling a force ghost. Then he thought of his friend's words, and realized the error of his ways.
Black, White or Grey?[]
Long have I taken lives and caused grief. Too long. All for the Sith. I wish to no longer be a dark terror to the galaxy. But the Jedi are ignorant fools. They do not see the power poossible for them if they were to look to the Force in its entirety. What is my fate?
—Darth Taikin
Taikin retired his Darth title, and left the Sith. He went to the grey Jedi. He began training, and became a Grey Knight.
At one point, He was hired by the Icy Hand, a criminal group, to kill a target, who was a Jedi. Taikin went to the Jedi's apartment. He was going to do it, but his lightsaber faltered. He ran away, and got a ship to Coruscant. He knew that he could never be a Jedi now, but he decided to offer a proposal to the council. He would work for the Jedi Order, but not be a part of it. This was accepted.
Ruusan[]
Taikin's first mission for the Order was to Ruusan. A disturbance in the Force had been felt near the Valley of the Jedi, and Taikin was sent to investigate. He went to the Valley of the Jedi. There he met a Bouncer. It told him that darkness was strong in the Valley. He watched from a distance, where he saw a group of strange beings in the middle of a dance. They wore masks, and carried strange weapons. He watched them from a distance. Their dance finished, and one of them (whom Taikin presumed to be the chief) signaled to his attendants. They went into a black tent and emerged with a wooden pole, to which a young Jedi was tied. His master was carried out on another pole. The tribe lit an enormous bonfire. At first, Taikin thought the two were to be burned, but the captives were not moved. The chief removed a strange flute from his pocket, and began to play. The Jedi and his padawan seemed to be losing their life force by the second. Taikin realized he needed to move fast. He executed a smooth flip, and, drawing his lightsaber in midair, sliced the flute in two on his landing. Instantly the two Jedi recovered. He threw them their lightsabers and they freed themselves. The beings drew their weapons, which looked to be made of some kind of energy, although different in nature to that of a lightsaber. The battle lasted for a few minutes, and then most of the beings fled into the night. Taikin caught one and questioned him. He soon learned that his enemies were part of an ancient order known as the Kotar Sith. They were once a part of the Sith, but they left it to pursue their leader, who had learned powerful Dark Side knowledge from an unknown Sith Lord. They now planned to return. Taikin sliced off his enemy's mask. He was shocked to discover that the being had no face, only a black void. The being suddenly began to dissolve, until it vanished in a cloud of smoke.
Report[]
Taikin returned to the Council and made his report. The Masters considered this unexpected chain of events. They found that the Jedi Archives contained brief references to the Kotar Siith, but no real information was found. The Jedi sent a group to gather any information from Ruusan. 25 Jedi went, but only three returned. They had learned enough about the enemy for the Jedi to prepare a defense team to protect the valley and defeat the Kotar Siith. The team comprised of some of the greater Jedi Masters of the time.
Final Battle[]
Taikin was appointed general of the strike team that was dispatched to the Valley of the Jedi. When they reached the valley, the leader of the Kotar Siith sent a large force to fight the Jedi. Taikin, wasting no time, went after him. He chased him through the valley, until he caught up. They engaged in combat. Taikin was strong, but his opponent was stronger. Taikin gradually weakened, until he could barely counter his opponent's strikes. Summoning his last reserves of strength and force ability, he force pulled the mask off the Siith's face. Taikin's enemy screamed and dissolved. Having used his last strength, Taikin collapsed.
Post Mortem[]
Taikin was cremated on a pyre in the Jedi Temple. The force ghost of Deslath Jhet appeared nearby and watched his friend's funeral. Taikin was given the rank of Jedi Master posthumously. His lightsaber was placed on display in the Hall of Relics.
Behind the scenes[]
This article took about a year, on and off, to write, because I got so busy and often had no ideas.