Logrus de Mordechai, better known as Mordred, is the last functioning antediluvian in this universe. He has claimed to have been born at the dawn of recorded time, although the first verifiable reference to the vampire in history doesn't appear until the 4th Century A.D. He is the leader of the Sabbat and is believed to be living on Wilke's Star, although crusader team veterans argue that it is impossible.
The only source for Logrus' early history is from the vampire's own lips; several people have recorded their conversations with the antediluvian over the centuries, which is why we know anything about him. Mordred says that he was born in the first city, Enoch, as referenced in the vampiric bible, the Book of Nod. Once he grew to manhood, he was considered quite gifted, and as a result was embraced as an eighth-generation (or tenth-generation) vampire. Therefore he was there when the Orb first appeared. He saw its power and how his brothers fought over it, and when Caine lost control of his childer, it led to the fall of the first city. Caine supposedly gave the Orb to a water spirit.
After the city fell, Mordred says he lived in ancient Babylonia, and then later moved to the west, living in Judea, then Egypt, and eventually moving to the center of the world. He pretended to be a quite successful merchant of questionable goods, and was present in Rome at the height of the Empire...and of vampiric influence. Eventually Logrus tired of the feuding between the vampire clans and went to Brittania -- where he was when the Western Empire collapsed.
As a powerful figure in Brittanic society, his advice was highly sought after. He supported the Roman general Arthur becoming king, and in exchange, Mordred (the Romans could not pronounce "Mordechai") was adopted as his son. This balance of power was acceptable to the vampire until a powerful mage named Merlin tricked a water spirit (later known as the Lady of the Lake) into surrendering the Orb. He in turn handed it over to King Arthur, who called it Excalibur. Logrus recognized the Orb for what it was, and fearing the damage it would wreck upon the kingdom, demanded the sword. Arthur refused and Mordred went into exile.
Logrus managed to unite the Brittanic tribes outside Arthur's control to build an army to capture the artifact. He managed to neutralize Merlin, weaken his best general (Sir Lancelot), and spread his best knights on a foolish quest. With all the advantages at his disposal, he moved his army to strike, where Arthur met him at the Battle of Camlan. Unfortunately, although unstoppable in his vampire form, Excalibur managed to paralyze Mordred when he was impaled by it. As a result, he was unable to stop the water spirit from reclaiming the Orb before he could posess it.
Unfortunately, this level of influence brought too much attention upon him, so he was forced to go into torpor until he was forgotten by the other vampires. Rumors of his appearance throughout the Middle Ages are uncertain; Mordred says he stayed hidden until the Renaissance. There again, he pretended to be a merchant, but began a new quest -- to become an antediluvian himself. He joined a group of like-minded vampires and proceeded to hunt down high-level vampires and diablerize them. Eventually, he rose to fourth-generation, and killed his companions.
The Rise of the Sabbat
Gehenna caused the rise of the antediluvians, but many of them were eventually destroyed by the Tech Infantry. Those that survived retreated to the Wraithlands, cementing their control over those vampires that survived the apocolypse. Mordred had gone into hiding rather than serve the antediluvians. Meanwhile, his enemies solidified their control over the vampire community. In 2196, the Black Hand made a deal with the Earth Federation to allow ghouls to join the Tech Infantry. In exchange, they took ownership of a system (later called Enoch) on the rim of known space. Two years later, when the Wraithlands become uninhabitable thanks to the Bug Asteroid that wiped out Earth, the antediluvians moved out and formed the Kingdom of Enoch.
With the Black Hand leadership on the Rim, Mordred made his move. Quickly gathering many vampire dissidents who opposed the antediluvians, Mordred reformed the Sabbat, and began challenging vampire controlled areas within the Earth Federation. This led to more defections, which caused Ventrue, the King of Enoch to declare Mordred a wanted criminal, and offer a high price for his heart. Ventrue also encouraged his allies in the Fed to hunt for Mordred as well, including the recently rescued Bruce von Eisenstein. In 2201, von Eisenstein found him and attempted to capture the wily vampire, only to be destroyed in turn. Mordred fled to Wilke's Star and formed a new headquarters there.
Gathering his strength, he decided to turn the manhunt against Ventrue. Leaking information that Mordred was on Wilke's Star with a strong army, Ventrue himself came along with the 10th Tech Infantry Legion, manned solely by Black Hand ghouls. In 2203, this force proceeded to fight a vicious campaign on the planet and won, but the sacrifice of the Sabbat army was part of the ruse. The conflict allowed Mordred to reach Ventrue, defeated him, and then diablerized him, finally becoming an antediluvian himself.
Outraged at the loss of their king, the new Queen of Enoch, Arikel, declared war on the Sabbat by any means necessary. Of course, the use of a Tech Infantry legion by a foreign power finally broke the treaty between the Black Hand and the Federation, and ghouls were kicked out of the Fed military.
War of Blood
Vampires slaughtered each other throughout the Fed, often in public, terrorizing the citizenry. After several ships from the Kingdom of Enoch were caught sneaking through Federation space, the Grand Council realized that the War of Blood needed to be contained. In 2209, the Tech Infantry created the Crusader division, forcing both Black Hand and Sabbat adherents to be more discreet. So the hot war became a cold war, but no less vicious.
In 2225, Mordred decided to eliminate the Black Hand's interference in Fed affairs. He supported the The Resistance during the 2nd Civil War, which led to the disasterous TI landing on Wilke's Star, which made the name of Brigadier-General Sarah Dunmeyer. That eliminated the Sabbat's active support in the human conflict, but the War of Blood continued on, led from that planet. In 2236, General Arthur Clarke is ordered to finally eradicate all vampires from the planet. Mordred is widely assumed to have died in that battle, but he actually remained dormant, hidden under a pile of rubble.
Now believed to be dead, Mordred was able to operate the Sabbat more effectively, without interference from Crusader Teams. By 2241, his operatives were on the move again, including Fabian Cortez. His most trusted lieutenant that is still alive is known as Santino and is considered one of Mordred's progeny. Magnus still serves as his chief war general. The Sabbat Chief Assassin Elizabeth was killed. Another noteworthy Sabbat member that currently serves Mordred is a vampire named Malikait. In 2238 Malikait embraced Melissa Cortona. She has been a rising star in the organization and diaborized a very high ranking member of the Black Hand during the war of blood. She is now considered to be the Sabbat's chief assissin.
He was able to infiltrate many of the Harrington daughter corporations and built their influence over the Fed. When he discovered the Orb had reemerged, he sent Xavier Pollos to retrieve it for him in 2243. This only led to him being betrayed when Pollos was possessed by al-Hazen.
Through secretly manuevering many bureaucrats through proxies, he was able to convince Earth Fleet to finally eliminate the vampire threat from the Kingdom of Enoch. In 2255, they used a Dooms Day Device on the Enoch system, killing Arikel, and decapitating the Black Hand leadership. Without an antediluvian to serve, the organization fell apart, leaving Mordred supreme.
End of the War of Blood
When the Federation fell following the Caal Invasion, Mordred sensed opportunity. He initially backed the Rump Federation of Joseph Smythe, offering his support and that of the Sabbat against the Holy Terran Empire in exchange for a new treaty, wherein his Sabbat would gain an alliance with the restored Federation much as the Kingdom of Enoch had many years before. The two would then combine forces to eliminate the remnants of the Camarilla once and for all and leave Mordred undisputed ruler of all Vampires. When their joint efforts to kill Vin Dane at the Battle of the Round Table not only failed but cost him the life of Fabian Cortez, his long-serving Ghoul, Mordred switched sides once again. As his brief alliance with the Federation had solidified his rule over Wilkes Star and allowed him to pry Van Diemen away from the Empire, he now offered both systems to the Empire in exchange for a patent of nobility naming him Duke over them. The Emperor signed a secret treaty allowing Modred and the Sabbat free reign over the two systems as a fiefdom under the Empire, provided they withdraw all Sabbat vampires from the rest of the Empire. Modred agreed, knowing he had yet another ace up his sleeve.
The fall of Ventrue and Arikel had enticed a long-lost Antediluvian out of hiding. Ennoia, the founder of Clan Gangrel, had failed to rise at Gehenna, and was thought long dead. In fact, she had merely waited for the rest of the Antediluvians to kill each other off in Gehenna and its aftermath, and now emerged at last. Even with the remnants of the Camarilla and Black Hand flocking to her leadership as the last survivor of the original antediluvians, she knew she did not have the forces or the resources to stand against Mordred and the Sabbat. Reasoning that if you can't beat them, join them, she had agreed to marry Mordred and unite the Camarilla and Sabbat at last under their joint leadership. Camarilla vampires not being covered by the Sabbat's treaty promise to withdraw from the Empire, they could still operate outside of Modred's formal domain without breaching the treaty, yet through his union with Ennoia, they still served his interests.
Rise of House Mallorean
Mordred now serves the Empire as head of House Mallorean, the name taken from Sir Thomas Malory, who had chronicled Mordred's killing of King Arthur in his Le Morte d'Arthur. It amused Mordred to name his new house after a past regicide of his, now that he once more was a high-ranking member of a Royal Court. His relationship with Ennoia is not public knowledge, and as far as anyone outside their inner circle knows, the Camarilla and Sabbat are still at each others' throats. The actual fighting is at the lowest level in centuries, but everyone else thinks that's just part of the Sabbat's efforts to "go legit" as part of the new power structure, the price they pay for their open domination of two systems. Their plans to unite vampires publicly under their joint leadership are delayed and complicated by the arrivel of another long-lost Antediluvian, Malkav, who has returned from his self-imposed exile in an extradimensional prison of his own hallucinatory making, following the curing of his madness by the Mind Oracle Andrea Treschi.
Behind the Scenes
Although he's Bax's former character, he actually never appeared in the TI universe as a former PC. Mordred was actually used in a tabletop campaign in which the concept was that antediluvians were weak from being asleep for centuries, and therefore were potentially killable. So they followed their characters through history, gradually becoming more powerful, and hunting down antediluvians. When Bax ran the TI game later, he became one of the major NPC's, because the players had ALL heard of how badass Mordred was.
Logrus is the name of the embodiment of Chaos in the Chronicles of Amber series by Roger Zelazny. Mordechai could just be a fun Hebrew name to throw in. He became "Mordred" because they played the Arthurian legend as an episode.