Overseer Luther was a Time Lord who secretly wanted to take over Gallifrey.
He and Uriel started the Final Chapter, a conspiracy to end Rassilon's policy of non-interference and turn Gallifrey into a military power. They were going to create clones from Uriel's biodata as their army. However, when Uriel saw his "first child"; Xanti, his military ambitions faded and he put his son in the Chapterhouse, then went into hiding.
Years later, Luther began a new secret sect called the Elysians. He made clones from Xanti's biodata as part of his plan to take over the Watchtower, rewrite history and rule Gallifrey. Luther's plan was defeated when Xanti was able to turn the Elysians against the Overseer. (COMIC: The Final Chapter)